# Using Fog lights without headlights & DRL's



## Doooglasss (Aug 28, 2009)

I've seen this a few times recently on a few forums and I've been posting an answer that isn't the most accurate.

Disclaimer: Remove your negative battery terminal before doing ANY electrical work. I am not responsible for you crossing wires, blowing fuses, relays or messing your car up. I've done a lot of electrical work in the past and feel comfortable- if you don't then don't do this.

OKAY this forum sucks. You can't post a LIVE link to a PDF so you guys can click below. I've retyped this post like 5 times now.

http://douglobue.com/ttfogs.pdf

Lets start with the wiring diagram. It's a PDF from the Bentley that I scanned in and took notes on while I was doing the work. Click the link above.

*DRL's*

I need someone with DRL's to confirm this up in Canadiaville. I believe we have the same headlight switches, but different wiring harnesses. My US harness is missing pins for 3, 5, 6, 9, & 12. Now I know pin 9 is the rear fogs but I suspect one of the others is a DRL function. Pin 5 specifically goes to fuse 17 which in a previous post we thought pulling would disable DRL's.

If someone north of the border wants to pull these pins that would be great. In order to pull the pins you're going to need a special tool. You can buy the ECS set for $60 and be able to pull all the pins on various engine harnesses. When I went to buy it, it was out of stock so I made do with this Lisle Tool that I ordered from a local tool store for $15. The only thing it doesn't do is the very small wiring harness pins such as those found on the coolant temp. sensor and throttle body connector. I plan on getting an ECS set after the holidays.

When you pull the pins out of this harness you insert the tool around the clip like any other harness but there is also a small plastic flap that holds the pin in- an added security. I was using a micro flat head and gently lifting the flap up while pulling on the wire and holding the tool in to the connector. With a little force everything comes out. I did snap one of the flaps off so be careful.
*

How to make fog lights work in the parking light position (without the headlights on)* 

In order to do this you need to remove pin 4 and attach it to the wire for pin 1.

Pin 4 is power to the a relay that provides switched power to the fog lights. It's a yellow/red wire.

Pin 1 is switched ignition power- when the key is in position two it's hot. It's a black/red wire (also one of the two thicker wires in the harness.

Under normal unmodified operation pin 4 doesn't receive power until the headlights are on. We are giving it power as soon as the ignition turns on. This wire will not be live when the ignition is off and it will not kill your battery. I feel like this is the safest way to do this because if you follow pin 4 before providing power to the headlight switch & fogs it passes through 15amp fuse S236.

In order to do this in what I thought was the safest way I pulled both pins 1 & 4 from the harness. I cut the connectors off for both of them at the same spot and purchased a new wide pin from VW to replace pin 1 with. Soldered all three exposed wires together and heatshrink/electrical taped them. To be clear I am completely removing pin 4 and not replacing it. We are only replacing pin 1.

I will post the part number for the extra pins up today. They cost me $12 for four pre-crimped connectors at VW. You obviously only need one- I like having extras and didn't know where this project would take me- or how many times I'd mess up.

I'm sorry I didn't take many photos. It's cold outside damnit!

I also installed a euroswitch at this time- it appears that Pin 9 is power for the rear fogs. I'm sure you wouldn't want to wire this directly to the rear fogs but maybe a fuse/relay system depending on a few factors. I don't own euro tails (yet) so I can't do this- when I do I'll update this thread.

To be clear you can do this with a regular headlight switch as well.

Got my whole dash together for the first time in three years, just to have to take it apart this weekend to do the gauges under the radio flap:










foglights on, headlights off:


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## l88m22vette (Mar 2, 2006)

It'd be cool to wire aux driving lights or something to the rear fog switch...hmmm


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## PLAYED TT (Oct 17, 2010)

l88m22vette said:


> It'd be cool to wire aux driving lights or something to the rear fog switch...hmmm


Like real fog lights?


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## TTurboNegro (Mar 9, 2007)

I'm confused, I need pics :banghead: 
These are the pins on back of h/l switch? And does switch pop right out? And are pins labeled?


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## PLAYED TT (Oct 17, 2010)

TTurboNegro said:


> I'm confused, I need pics :banghead:
> These are the pins on back of h/l switch? And does switch pop right out? And are pins labeled?


1?
2 no
3 probably not


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## l88m22vette (Mar 2, 2006)

The Bentley has all the info/pictures you need



PLAYED TT said:


> Like real fog lights?


Yup...I've really gotten the itch to go rally-style with my TT, but TBD


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## PLAYED TT (Oct 17, 2010)

l88m22vette said:


> The Bentley has all the info/pictures you need
> 
> 
> 
> Yup...I've really gotten the itch to go rally-style with my TT, but TBD


I want to put some in the lower grilles, but I'm too lazy and I feel like it's not worth it for the 5 times a year that I drive through fog.


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## Doooglasss (Aug 28, 2009)

Yes we are modifying the headlight wiring harness. This is the plug that goes into the headlight switch. We are not modifying the actual switch. Remove your lower dash, unplug your headlight switch & OBD port from it. Unscrew the fuse panel and move it down- then you will have all the room in the world to work on this.

Yep the pins are labeled and I also gave wire colors so you can confirm with that. If you read the wiring diagram you will find other info if you need it too.

James- I think people were taking RS4/6 lower grilles with fogs and modding them to fit our cars. I have photos I could dig up somewhere...


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## PLAYED TT (Oct 17, 2010)

Good idea. I'll look into that


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## Doooglasss (Aug 28, 2009)

James:


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## slush puppie (Oct 3, 2009)

doug, do you make house calls?

:laugh:


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## Doooglasss (Aug 28, 2009)

haha- only on Long Island!


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