# Euro switch leds



## Treg67k (Jul 14, 2004)

*Euro switch leds - MOD WORKS!!*

- Does anyone know if the Euroswitch has the led for the rear fog light like the standard US spec switch has for front fog lights (turns green when switched on)?
If not, has someone done a mod like shown on http://irc.junglist.org/fogmod/foglighticon2.html. Or does that mod apply only for Jetta, GTI etc.


_Modified by Treg67k at 7:53 PM 11-6-2005_


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## DenverBill (Apr 18, 2003)

*Re: Euro switch leds (Treg67k)*

No LED in the switch.


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (DenverBill)*

Too bad - I am exporting the car to Europe in short while and will need some kind of indicator for the rear fog. I looked up my panel and do not seem to have the right type of icon under the speedo.
Anyone into circuit boards who'd know how to add the led to the switch?


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## touareg007 (Jan 21, 2005)

*Re: Euro switch leds (Treg67k)*

Yes it does.


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (touareg007)*


_Quote, originally posted by *touareg007* »_Yes it does.

Could you elaborate a bit more i.e. what were you referring to. Thanks.


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## DenverBill (Apr 18, 2003)

*Re: Euro switch leds (Treg67k)*

I just double checked my switch -- no LED; as opposed to my Boxster, which does have a green LED for the rear fog, and an amber LED for the front fogs.


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (DenverBill)*

...Wonder if those would be interchangeable...I know it is lot to ask but could you send me a picture of the circuit board of your boxter's switch...or is the boxter's switch totally different?


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## spockcat (Jun 5, 2003)

*Re: Euro switch leds (Treg67k)*


_Quote, originally posted by *Treg67k* »_...Wonder if those would be interchangeable...I know it is lot to ask but could you send me a picture of the circuit board of your boxter's switch...or is the boxter's switch totally different?

Yeah, disassemble your Boxster's switch and take a picture of it will you?


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (spockcat)*

...relax...if it is using the same construction as vw switch does it is a three minute job to disassemble/assemble that. Only thing you'll need is size 6 torx bit. 
As I noted before, if it is totally different construction from VW switch then just ignore my question.


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (Treg67k)*

ok...looked some boxter dashboard photos and the switch looked different. However, also looked up some Cayenne photos and the switch looks similar. Anyone in the forum with Cayenne that could validate whether they have the rear fog led on the switch?


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## 4x4s (Dec 18, 2003)

*Re: Euro switch leds (Treg67k)*

There was a post here over a year ago with a link to a site that showed how to wire in the LED. IIRC, the circuit board in the Touareg Euro switch is configured for the LED's, but they are not installed. Unfortunately, I can't remember any unique words or phrases in that post to help narrow it down in a search.


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (4x4s)*

you may be referring to the circuit board mod behind the link on my first post (see above)? I opened the Touareg switch yesterday and the layout is different from the one in the photos on that page.


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## 4x4s (Dec 18, 2003)

*Re: Euro switch leds (Treg67k)*

That may have been it, but I thought there was a Touareg owner who tried it and was successful - I may be wrong though.


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (4x4s)*

I also sent e-mail to the guy who had designed the mods and he's not familiar with the Touareg switch.


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## FrankS (Feb 25, 1999)

*Re: Euro switch leds (Treg67k)*

I checked with the Touareg Freunde in Germany how the usage of the rear fog light is indicated, they confirmed that there is no (amber/yellow) LED in the switch itself but there is one in the dash, they posted a picture of a US- spec car and it does have the symbol. Click here for the full story (in German) and the picture
Regards
Frank


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (FrankS)*

Thanks, I have been looking into both US and Euro switch circuit boards and start to understand how they function. Pin 4 is the power input to the switch according to Bentley (and my investigation as well). Does someone know what the input voltage is? Standard 12v?


_Modified by Treg67k at 3:18 AM 9-30-2005_


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## touareg007 (Jan 21, 2005)

*Re: Euro switch leds (Treg67k)*

Why is having this LED is so crucial if the rear fog light is not used very often anyway...


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## 4x4s (Dec 18, 2003)

*Re: Euro switch leds (touareg007)*


_Quote, originally posted by *touareg007* »_Why is having this LED is so crucial if the rear fog light is not used very often anyway...

He will be needing it to meet Euro regulations:

_Quote, originally posted by *Treg67k* »_Too bad - *I am exporting the car to Europe in short while and will need some kind of indicator for the rear fog.* I looked up my panel and do not seem to have the right type of icon under the speedo.
Anyone into circuit boards who'd know how to add the led to the switch?


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (Treg67k)*

I've may have figured out a way to make a simple mod to the switch itself. If it works, it is relatively straight forward - not really elegant circuit board design - but should be good enough to meet the regulations.
It may be some weeks to come before I'll try this as first I will try to figure out if among Audi/Porsche parts they'd have a similar switch with built in leds.


_Modified by Treg67k at 2:43 PM 9-30-2005_


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (Treg67k)*

You can find the circuit diagram of the switch that I put together on the msn groups site:
http://groups.msn.com/touareg/...D=186
And here's link to the mod design. Note that this has NOT been tested yet on other than circuit board design program:
http://groups.msn.com/touareg/...D=188



_Modified by Treg67k at 4:40 PM 9-30-2005_


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## chessmck (Dec 22, 2003)

*Re: Euro switch leds (Treg67k)*


_Quote, originally posted by *Treg67k* »_Too bad - I am exporting the car to Europe in short while and will need some kind of indicator for the rear fog. I looked up my panel and do not seem to have the right type of icon under the speedo.

Interesting as my V6 2004 vin # 23xxx does have the light in the dash and it turns on after I added the fog lamp and euro switch.... w/o any vag mod. Maybe you have a later VIN and they removed the light.


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (chessmck)*

Yep - vin (as stated in my nickname) indeed higher...2004 - 67k. They have put trailer signal indicator on the panel instead of the rear fog light.
Anyway - I enhanced my mod design a bit and should get yellow light on the switch itself for rear fogs. Bought the parts from Radio Shack yesterday for few dollars. I will install this mod to my car in December. See:
http://groups.msn.com/touareg/...D=189


_Modified by Treg67k at 11:51 PM 10-1-2005_


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## joeofthemountain (Jan 9, 2005)

*Re: Euro switch leds (Treg67k)*

Thanks for the schematic. I'd like to try it myself as I find it is very easy to activate the rear fogs unintentionaly.


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## jonee (Feb 25, 2004)

*Re: Euro switch leds (joeofthemountain)*


_Quote, originally posted by *joeofthemountain* »_Thanks for the schematic. I'd like to try it myself as I find it is very easy to activate the rear fogs unintentionaly.

Unintentional? Which manoeuvres do you make to unintentionaly pull a button in that location? Some people take hours to even find that button.
For what it's worth, here's a pic of my dash when front and rear fogs and handbrake and high beams are on:


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (jonee)*

Thanks for the photo. The indicators on the panel of my car are slightly different and I think I do not have the rear fog light on the panel. That's the reason for the mod design. As said, the mod should be relatively straight forward to implement and to my knowledge sufficient to register the car within EU.


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## spockcat (Jun 5, 2003)

*Re: Euro switch leds (Treg67k)*


_Quote, originally posted by *Treg67k* »_Does anyone know if the Euroswitch has the led for the rear fog light like the standard US spec switch has for front fog lights (turns green when switched on)?
If not, has someone done a mod like shown on http://irc.junglist.org/fogmod/foglighticon2.html. Or does that mod apply only for Jetta, GTI etc.

I noticed something in my car this evening that should be of interest to you. This evening I used my front fog lights. I have the Euro light switch and normal indicator in my instrument panel for the front fog lights. 
When the front fog lights are not on, the Euro switch shows a red tracing for the front fog lights. When you pull the switch out to illuminate the front fog lights, the red tracing becomes green. 
I don't have the rear fog wired but and I have bent back pin 7 so it doesn't give a false alarm if I pull it out too far. But I have to assume that the rear fog would work in the same way; the outline tracing of the rear fog turns from red to green when it is illuminated.
Anyone with the rear fogs wired care to check this?


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## mml7 (Dec 3, 1999)

*Re: Euro switch leds (spockcat)*

Sorry, no indicator for rear fog on the Euro switch. I have the rear fog indicator on the dash only. I also fiddled with the Central Elect. coding (added 32 per Ross Tech's writeup.


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## spockcat (Jun 5, 2003)

*Re: Euro switch leds (mml7)*


_Quote, originally posted by *mml7* »_Sorry, no indicator for rear fog on the Euro switch. I have the rear fog indicator on the dash only. I also fiddled with the Central Elect. coding (added 32 per Ross Tech's writeup.

Really? You have it wired and when you pull it out all the way to engage the rear fogs the tracing outline next to the switch doesn't change color like it does for the front fogs? I am very surprised.


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## 850T5 (Feb 10, 2005)

*Re: Euro switch leds (spockcat)*

Hi spockcat,
just tried it out on my T-Reg.
Front fog lights on: Indicator in dash goes on and on the EURO switch it changes color from red to green.
Rear for light on: nothing changes in dash or on the switch.
Mostlikely I will run into problems with the TÜV when I move back to Germany because of this missing indicator.
Actually I think the in-dash indicator is mandatory, no matter what the switch indicates. So I might end up with replaceing the US dash display unit with the German one.....


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## mml7 (Dec 3, 1999)

*Re: Euro switch leds (spockcat)*


_Quote, originally posted by *spockcat* »_Really? You have it wired and when you pull it out all the way to engage the rear fogs the tracing outline next to the switch doesn't change color like it does for the front fogs? I am very surprised.

Yup, I have the rear fog wired. LEDs in the switch only change color for the front fogs, not the rear. When I initially installed the rear fog, I hadn't bothered to recode the Cent Elect. since everything was working properly (i.e. dash light indicator for both front and rear). Toggling +/- 32 to the coding didn't result in any changes either to the dash lights or to the switch LEDs.


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (spockcat)*


_Quote, originally posted by *spockcat* »_
Really? You have it wired and when you pull it out all the way to engage the rear fogs the tracing outline next to the switch doesn't change color like it does for the front fogs? I am very surprised.

I analyzed the circuit board of the euro switch and there is no functionality on the board to change the led color as for the front fogs. Those components are missing and the board designs that I posted earlier on the msn site will provide that.
I moved back to Finland last week and am not sure yet if the indicator on the switch is sufficient for registration. I suspect it will be ok if I apply for special permission for that (special permission costs 275 euros i.e. multiple times cheaper than replacing the instrument panel). This is still all speculation as the car is now in a container somewhere on Atlantic.
Another interesting fact that my dealer in US told for shipping was to back the car into the container to enable jump start in case the battery will drain out. They told it might not drain out if I shut all windows and doors, lock the car with the key (not with the remote) and bring the key far enough from the car.


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## jinxegg (Oct 14, 2004)

*Re: Euro switch leds (850T5)*


_Quote, originally posted by *850T5* »_....Actually I think the in-dash indicator is mandatory, no matter what the switch indicates. So I might end up with replaceing the US dash display unit with the German one.....









I think it will be your best bet.


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## joeofthemountain (Jan 9, 2005)

*Re: Euro switch leds (jinxegg)*

My 2004 Treg is VIN 77something. The rear fog icon is present in the usual location but does not illuminate.
Anyone take the dash apart? Is it similar to the older VW/Audi designs that had necessary wiring -- but did not include the indicator bulbs? In other words, could we just add a lamp or LED to the speedometer circuit board?


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (Treg67k)*

Checked with the registration office and led 'inside' the car is sufficient i.e. the indicator light does not need to be on the instrument panel. I will not need any permits for this.
This means that if I manage to make the mod onto the switch I do not need to care about the indicator light on the panel and I will save lots of money.
Where can I find the best instructions for wiring the rear fog light? I found one set of photos, but am not sure if that I found the best instructions.


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## Vega (Jul 28, 2004)

I've run into the same problem after installing the rear fog light. If I shine a flashlight on the dash I can see the outline of the rear fog light indicator. The rear fog light works fine, but neither with or without vag'ing the code I cannot get it to light up. Has anyone found the reason why it works for some T-Regs and not others?


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (Treg67k)*

The mod works





















- still waiting for the car to arrive, but completed the mod to the switch and tested that as well.

















PS, to all those German people in US planning to export the car to Germany I very much doubt that you'd need anything else as rear fog light indicator than this type of light on the switch. I am making this assumption as my current rental, Ford Mondeo, does not have indicator light on the instrument panel but only on the switch. Also a quote from http://bundesrecht.juris.de/bu....html: "(5) Eingeschaltete Nebelschlußleuchten müssen dem Fahrzeugführer durch eine Kontrolleuchte für gelbes Licht, die in seinem Blickfeld gut sichtbar angeordnet sein muß, angezeigt werden. "
_Modified by Treg67k at 7:44 AM 11-7-2005_


_Modified by Treg67k at 8:15 PM 11-7-2005_


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## teledawg (Apr 17, 2004)

*Re: Euro switch leds (Treg67k)*

Treg67K,
Congrats, it looks like your rearfog indicator mod was sucessful. Can you provide any more info on what parts you used, etc. The schematic looks good, but some pics of the modded euro switch circuit board and a parts list would be most helpful to others who would like to do this mod as well.
Thanks for sharing,








T.D.


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (teledawg)*

Thanks - I will provide more detailed photos of the slightly modified ciruit (as the I was unable to get the same parts from RadioShack that I had on the plan) as soon as I have some time for this.
Also I'll provide more detailed info on how I connected the external circuit onto the switch. Good thing about this process was that the modifications to the switch itself were marginal.
Now I need to fill in all the customs forms etc. to get the cars out of the harbor. The cars are supposed to arrive today and I should be able to get hold of those either next or the following week depending on the customs process.



_Modified by Treg67k at 3:07 PM 11-13-2005_


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (850T5)*


_Quote, originally posted by *850T5* »_Mostlikely I will run into problems with the TÜV when I move back to Germany because of this missing indicator.
Actually I think the in-dash indicator is mandatory, no matter what the switch indicates. So I might end up with replaceing the US dash display unit with the German one.....








 
I doubt that you'd need an indicator on the display - on dash you'd need one (e.g. on the switch) - see my post above.


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (Treg67k)*

Finally ready - routing the lead from the control through the grommets was painful but definitely worth it. 
Everything seems to work, the small box with the indicator light mod is attached to the back of the dashboard with extra powerful velcro tape.
Box with the mod:









Modified switch. I removed one bridge from the right side of the switch (above the top wire on the right and to the right of the two 10k and 33k resistors). The two wires bottom right are connected to the yellow led for the rear fog light:








Lead from the control unit:








Switch with the indicator light (not very visible when picture taken using flash):








Result:









_Modified by Treg67k at 6:40 PM 12-4-2005_


_Modified by Treg67k at 6:41 PM 12-4-2005_


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## mml7 (Dec 3, 1999)

*Re: Euro switch leds (Treg67k)*

It doesn't appear like a European license plate fit on the rear of a US spec'd Touareg. The cut out looks too small. Do you also have to replace the rear hatch?



_Modified by mml7 at 1:33 PM 12-3-2005_


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (mml7)*


_Quote, originally posted by *mml7* »_It doesn't appear like a European license plate fit on the rear of a US spec'd Touareg. The cut out looks too small. Do you also have to replace the rear hatch?


No need to change that. They give you smaller license plates for cars imported from US. 
After all, importing car from US ended up being really straight forward process. The most complex things were the mod on the switch and pulling the lead from the convenience control unit thru the grommets.


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## sierradeux (Dec 4, 2005)

*Re: Euro switch leds (4x4s)*

Here is the link to the original article re: adding an LED to the Euro switch for the rear foglight telltale. 
http://irc.junglist.org/fogmod/index.html
There are apparently two different models of this switch, with different circuit boards. The reference I am giving dicusses the first type, and contains the link to the second type. That second design is the one illustrated earlier in this thread. A revieew of this current reference may solve some confusion generated so far. 
I plan on persuing this further as soon as my switch arrives.


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (sierradeux)*


_Quote, originally posted by *sierradeux* »_Here is the link to the original article re: adding an LED to the Euro switch for the rear foglight telltale. 
http://irc.junglist.org/fogmod/index.html


The mod described at that page is for old VW switches, not for Touareg. The circuit board on Touareg switch is very different. See below:
The circuit board at the mentioned page:








Touareg euroswitch circuit board:









_Modified by Treg67k at 8:12 PM 12-5-2005_


_Modified by Treg67k at 8:13 PM 12-5-2005_


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## sierradeux (Dec 4, 2005)

*Re: Euro switch leds (Treg67k)*


_Quote, originally posted by *Treg67k* »_
The mod described at that page is for old VW switches, not for Touareg. The circuit board on Touareg switch is very different. See below:
The circuit board at the mentioned page:








Touareg euroswitch circuit board:









_Modified by Treg67k at 8:12 PM 12-5-2005_

_Modified by Treg67k at 8:13 PM 12-5-2005_

Thanks for that info. What you have done appears very elegant. However, I don't think that I could duplicate it, based on what has been posted so far. The circuit diagrams, as I have chased up from your msn postings, don't give me enough information to correlate with your photographs.
Can you please supply:
1) a list of materials, (presumably obtainable at Radio Shack, or equivalent electronics vendor).
2) Illustrations of the back sides of both the switch board, and your constructed circuit board, so that one can see exactly what is soldered to where. I am specifically interested in how and where you fastened the new LED(s) to the switch board. 
3) Any further instructions which would enable easy duplication of your project. 
Thanks very much.


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (sierradeux)*

Indeed, it would be very difficult to replicate with the provided photos...sorry








However, I plan to write much better instructions with photos of all relevant components of the mod. But this will be after Christmas







as now I am on the road and when getting back to my house I need to put all the stuff that came out of 313 moving boxes into their places.
Anyway, I was extremely happy about thís mod as it enabled me to get the car thru the import registration process with close to 0 cost and now I can spend the money for a Webasto, which will be very useful in Finnish winter. 
The only other things that I needed to do was to replace the yellow parking lights with white ones (or actually blue ones for Touareg) and to buy the emergency triangle. They also require the VIN carved on the body (not on the window), but that you'll find on the right side of the spare wheel in the trunk so I did not need to do anything there either.


_Modified by Treg67k at 2:43 PM 12-8-2005_


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## 850T5 (Feb 10, 2005)

*Re: Euro switch leds (Treg67k)*

I'm also in need to have this mod done prior moving to Germany next year.
This pictures from the Euroswitch board might help to figure out what needs to be done:


















_Modified by 850T5 at 7:14 AM 12-11-2005_


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## basim (Nov 11, 2005)

When the rear fog light is swtched there should be a wire or contact which gets the voltage to switch the light on. 
Would it be possible to hijack that contact and attach a LED on it. The LED could be glued under the front panel of the switch.
Those who changed the american switch for a european one can use the panel of the old useless switch. Whenever the car is through the checkings, one could put the old panel of the switch back.


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## sierradeux (Dec 4, 2005)

*Re: (basim)Euro Switch LED for rear fog*

I have thought about the same issue, while waiting for Treg67K to publish the "how to" for his elegant LED fix posted above. It has occurred to me that one might hook an LED directly into the rear fog trigger wire, which is on pin 7 of the Treg euro switch. However, the I don't yet know the voltage on that pin with the rear fog turned on. I have just made a little probe so that I can measure it with my VOM, and if it ever stops raining, I'll go out and measure it. With the complex electronics on this vehicle, I wouldn't be surprised if it were not 12V.
However, if 12 volts is the answer, Radio Shack sells a nice little pre-wired diode harness, designed to run on 12V, available in several colors, which could be wired into the dash instrument cluster as a rear fog telltale, even better than into the switch. 
I'll post an answer as soon as I have measured the voltage, or has anyone else tried this? Would the extra draw to an LED here screw up the control module?


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## Treg67k (Jul 14, 2004)

*Re: (basim)Euro Switch LED for rear fog (sierradeux)*


_Quote, originally posted by *sierradeux* »_However, if 12 volts is the answer, Radio Shack sells a nice little pre-wired diode harness, designed to run on 12V, available in several colors, which could be wired into the dash instrument cluster as a rear fog telltale, even better than into the switch. 


The voltage coming out of pin #7 should be 12 volts, but most likely adding a prewired led 'behind' pin #7 would lower the voltage to such low level that the convinience control unit may not work correctly (I do not know). 
However, I will have a look into the circuit board to identify if some other pin could be used. Anyway, that Radio Shack prewired 12 volt led system is anyway an excellent idea.

_Modified by Treg67k at 8:40 PM 1-6-2006_


_Modified by Treg67k at 7:19 PM 5-4-2006_


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## Treg67k (Jul 14, 2004)

*Re: (Treg67k)*


_Quote, originally posted by *Treg67k* »_
However, I will have a look into the circuit board to identify if some other pin could be used. Anyway, that Radio Shack prewired 12 volt led system is anyway an excellent idea.


You may be able to make this work if you connect the input for this led (with the built-in resistor) to pin #7 and the output to pin #6 (ground). 
I would recommend testing this by connecting the positive connector of an external power supply to pin #4 and the negative to pin #6. Also connect the led harness as stated above.
Here's the link to the radioshack harness. Note that to comply with European regulations this needs to be yellow light.
http://www.radioshack.com/prod...earch
_Modified by Treg67k at 8:54 PM 1-6-2006_


_Modified by Treg67k at 9:05 PM 1-6-2006_


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## sierradeux (Dec 4, 2005)

*Re: (Treg67k)*


_Quote, originally posted by *Treg67k* »_
You may be able to make this work if you connect the input for this led (with the built-in resistor) to pin #7 and the output to pin #6 (ground). I would recommend testing this by connecting the positive connector of an external power supply to pin #4 and the negative to pin #6. Also connect the led harness as stated above.


Well now things are getting very interesting.
With the switch pulled out of the dash, but still hooked onto the harness, I probed the wire on pin 7. With the lights off, I read 4.5 volts; with the parking lights on, and the switch pulled to rear fog, I read 0 volts. That has me scratching my head.
I then took the switch to my test bench. With +12 volts on pin 4, and ground on pin 6, the LED’s in the switch bezel and turn button lit up red, just as they should. In all cases where the fogs were active, the rear fog telltale turned green. 
I then measured voltages in all possible combinations. Results are as follows:
Note: empty spaces mean 0 volts

Lights off pin 2 = +12v pin 5 = +6.5v 
Auto (during daytime) pin 5 = +6.5v 
Parking lights pin 2 = +12v pin 5 = +6.5v 
+ front fogs pin 2 = +12v pin 5 = +6.5v pin 10 = +1.5v
+ rear fog pin 2 = +12v pin 5 = +6.5v	pin 10 = +1.5v

Headlights pin 2 = +12v pin 5 = +6.5v 
+ front fogs pin 2 = +12v pin 5 = +6.5v	pin 10 = +1.5v
+ rear fog pin 2 = +12v pin 5 = +6.5v pin 10 = +1.5v

This makes things pretty confusing, trying to figure out what that switch is doing on the rear fog circuit, though the change in the harness wire on Pin 7 suggests that some sort of positive feedback to ground is being used. Without a wiring diagram, it’s hard to know what the explanation is. I therefore question my thoughts about a simple 12volt LED across pins 6 & 7.
Any help out there?











_Modified by sierradeux at 3:05 PM 1-10-2006_


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## Treg67k (Jul 14, 2004)

*Re: (sierradeux)*


_Quote, originally posted by *sierradeux* »_
With the switch pulled out of the dash, but still hooked onto the harness, I probed the wire on pin 7. With the lights off, I read 4.5 volts; with the parking lights on, and the switch pulled to rear fog, I read 0 volts. That has me scratching my head.


Now I remember why I hooked up the 12 volts from pin #4 thru the transistor to the pin #7 and to the rear fog led....
Just a though i.e you might be able to make this work if you hooked up the prewired led harness from pin #4 with pin #7 i.e. when the rear fog is not on, the voltage differential is too small for the led to illuminate, but when the rear fog is on the voltage differential is sufficient.


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## sierradeux (Dec 4, 2005)

*Re: (Treg67k)*


_Quote, originally posted by *Treg67k* »_
Just a thought - You might be able to make this work if you hooked up the prewired led harness from pin #4 with pin #7 i.e. when the rear fog is not on, the voltage differential is too small for the led to illuminate, but when the rear fog is on the voltage differential is sufficient. 


Pursuing this further, I decided to put the LED harness on the test bench to see what the ilumination parameters are. It is actually a little too bright at 12V, and as I reduce the voltage, it comes down to a comfortable level to be used as a telltale in the instrument cluster, probably put in along the bottom edge between the tach and the oil temp gauge, at the level of the clock and odometer reset buttons. 
Unfortunately, the LED doesn't go out until the voltage is dropped to about 2.5V, so I will need to insert some resistance to drop the potential difference from 12-4,5=7.5 volts with the switch turned off, down to about 2 volts, to keep the LED dark. Inserting a resistor into the LED harness should be easy enough, but I'm not sure what size to buy.
I need help with this calculation. Thanks


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## Treg67k (Jul 14, 2004)

*Re: (sierradeux)*


_Quote, originally posted by *sierradeux* »_
I need help with this calculation. Thanks









Could you tell the coding (either the colored stripes or the number coding) of the current resistor - I'll help you with this one.


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## depiry (Feb 16, 2005)

Resistance for a LED to operate at 12V is 330 ohms ,add another 330 ohm in series or two in series.


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## sierradeux (Dec 4, 2005)

*Re: (Treg67k)*


_Quote, originally posted by *Treg67k* »_
Could you tell the coding of the current resistor?

Resistor built into the orange plastic housing appears to be 580 ohms (green, gray, brown). I had a pack of 330 ohm resistors in the house, so I started adding them in series in front of the LED. It certainly dims the LED down to a usable level for the instrument panel, but with an additional 1000 ohms (3 resistors) added in series, the LED still glows dimly at 2 volts. which means that it would still be illuminated at the 7.5 volts present with the light switch "off". That's no good for an instrument panel telltale. Perhaps I should get a 1K ohm resistor, and then try another 330 in series with that, or do you have better idea. Obviously I'm slowly working toward your solution for this issue, and perhaps I should just wait for you to publish it. http://****************.com/smile/emthup.gif 
How much resistance did you end up with in front of your LED?
Thanks for the help http://****************.com/smile/emthup.gif 


_Modified by sierradeux at 11:09 AM 1-13-2006_


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (Treg67k)*

Here's the actual circuit of the mod that I did earlier with parts listed:










The yellow led itself is not attached to the circuit board - it is simply pushed into the appropriate 'cell' within the switch. You'll understand what I refer to with 'cell' when you open the switch.

I also drew a simplified version (with parts listed):











_Modified by Treg67k at 3:50 PM 1-16-2006_


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## sierradeux (Dec 4, 2005)

*Re: Euro switch leds (Treg67k)*

Thanks for the great set of schematics. I decided to build the simple version since I really wanted to put the LED in the instrument panel. All parts were easily located at Radio Shack. In addition to the parts on the schematic, I used the following:
Yellow LED 3v 20ma 55mcd Radio Shack part # 276-021
Panel Mount LED holder Radio Shack part # 276-080
Enclosure with PC board Radio Shack part # 270-283A
The control box looks like this:








and the wired harness looks like this:








With the bottom panel removed from below the steering wheel, there is a nice flat shelf between the two screw sockets to securely stick the control box down with velcro strips, as Treg67k has suggested.
Instead of modifying the light switch itself, I wired the mod into the wiring harness behind the switch, soldering and taping all connections thus:








after which I taped up the harness before reinstalling the light switch.
When I looked behind the instrument panel, I discovered that I would have had to tear everything down to get to the space just to the right of the oil temp gauge where I wanted to install the LED, so I changed my plan, and installed it just above and to the left of the light switch:








The LED is not directly in my line of vision that way, while still announcing its presence when lighted. If it is still too bright at night, I can always add more resistance in the wire between the control box and the LED. The wire is easily accessible when the fuse box cover panel is removed.






























_Modified by sierradeux at 4:31 PM 1-18-2006_


_Modified by sierradeux at 4:32 PM 1-18-2006_


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (sierradeux)*

Cool...congratulations!!








If you want to make the light dimmer you can also remove one of the parallel 1kOhm resistors.


_Modified by Treg67k at 12:33 PM 1-19-2006_


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## sierradeux (Dec 4, 2005)

*Re: Euro switch leds (Treg67k)*


_Quote, originally posted by *Treg67k* »_If you want to make the light dimmer you can also remove one of the parallel 1kOhm resistors.

True, but the control box is now installed deep in the dash, whereas I have left a loop of LED harness accessible beside the fuse panel, so I can easily modify it there, if needed. So far it's fine, because it's out of my direct line of vision. I'll know better after a foggy night drive.
ADDENDUM: The silver mount for the LED was a little bright, too reflective. I put a small strip of black tape around it to match the other gauge enclosures on the dash, and I used a black magic marker on the inner rim to diminish the reflections. The LED is now at the correct intensity.
Thanks for your help! http://****************.com/smile/emthup.gif











_Modified by sierradeux at 5:05 PM 2-5-2006_


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## Treg67k (Jul 14, 2004)

*Re: Euro switch leds (sierradeux)*

Glad that it worked out!!


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## alaska_siberian (Dec 22, 2008)

*Re: Euro switch leds (Treg67k)*

Hi newbie here so bear with me.
1) Has anyone attempted this on an 08 Treg? Any instructions?
2) This seems like a nightmare compared to just running a set of wires back there on a separate switch.
siberian


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## Luzy V8 (Jan 10, 2008)

*Re: Euro switch leds (850T5)*


_Quote, originally posted by *850T5* »_I'm also in need to have this mod done prior moving to Germany next year.
This pictures from the Euroswitch board might help to figure out what needs to be done:









_Modified by 850T5 at 7:14 AM 12-11-2005_

Hi,
a couple of weeks go a friend brought his (I think 2005) Touareg to Germany. After installing the rear fog light, he modified the Euro switch by simply soldering another LED on the lower left empty spot on the circuit board. 
I guess this switch and/or circuit board is used in other vehicles too (other VW and Porsche cars) where a LED is already added by the manufacturer. 
I will try to find out the specification for the necessary LED.


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## thisbenguy (Jan 19, 2008)

*Re: (sierradeux)*

So would it be reasonable to assume that if I were to hook VW part 000 979 133 into a Euro switch at Pin 7 (after vag to ROW) I could use it in conjunction with a relay as a switch for a secondary set of fogs.


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