# Help Me Destroy Oil Light Buzzer



## 98xj (May 17, 2011)

'87 Jetta GLI 1.8 8V 5 speed. Oil light/buzzer continues to go blink and buzz at random. Tested oil psi with mech. gauge and its great all the time. Replaced both pressure sensors on block and above filter, cleaned all electrical connections in engine bay related, no fix. Where is the physical buzzer unit behind the cluster and can I remove it/unplug it? The light won't bother me but the buzzer is another story, and the speakers I have in the car don't drown it out. Help would be greatly appreciated.


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## Fat Rabbit (Nov 18, 2001)

First -- you should be running 10W40 or 15W50. The heavier oil the better. If you are using lighter weight oil your VW doesn't like it. It is buzzing to tell you so. 

Now to answer your question. The buzzer is on an "L" shaped circuit board behind the spedometer in the cluster. It's got a fancy name "Dynamic Oil Pressure Warning System Control Unit." When all else has failed to stop the buzz I have replaced a few of the circuit boards. Meanwhile -- want to buy my old boom box?????

To access the PC board you need to remove the cluster, then remove the foil printed circuit and the spedometer from the cluster. I'd put a new (used) circuit board in if I went to all the trouble to access it. Never can tell when the buzz might be meaningful.

BTW -- good job checking the oil pressure -- FR


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## 98xj (May 17, 2011)

Awesome info thanks for the reply. I'm running 10w30 now and it about due for a change so ill run 10w40 and see if it helps. Is there a way to just unplug the l shaped buzzer piece, because I've heard of a lot of the mk2s with the same issue so it'll be a crap shoot if a used one fixes it. Thanks


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## Fat Rabbit (Nov 18, 2001)

The oil grade should depend on where you live. 10W40 is minimum. Even in Northern Wisconsin where lows of -10*F are common several weeks a year I ran 10W40 most of the year with 15W50 or 20W50 during Summer months. I used a block heater during the very coldest weather to aid in starting.

I actually found very few bad PC boards over the years. Usually it oil viscosity or a bad sensor, grounded wire etc. That the issue might be oil grade is likely even more true as we set heat records across the US. Once you get to the PC Board you can neuter the buzzer. Its not quites as simple as hitting it with a hammer while cussing loudly but easily done with a wire clipper or soldering gun. FR


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## WaterWheels (Aug 14, 2005)

One tell-tale symtom of a bad circuit board, one (1) mind you, is the buzzer and light going off around 2000-2500RPM and staying on until the engine is shut off and restarted. Then at about the same engine speed it will happen again. I disable the warning system from under the hood on most of my cars because I use a mechanical gauge, but if it will also work if the circuit is bad, I don't know for sure as the tachometer also comes into play (coil signal really). It's a simple matter of grounding the high pressure wire and leaving the low pressure wire open. You lose the oil warning light when you first turn the key to ON this way too, but when you run a mechanical gauge who cares.


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## 98xj (May 17, 2011)

Thanks waterwheels, that's pretty much exactly when my buzzer starts going off around 2-2500rpm usually in 2nd or 3rd gear and sometimes it will stop itself and other times it will go off for 20 minutes (no s**t). Sometimes i'll throw in the clutch and shut it off to restart it while crusing but it'll usually come right back so sounds like the circuit board is my issue. Thanks a TON! You mentioned the high and low psi switches to bypass yours, how can I do this to mine? The thought of hitting it with a hammer and cussing happens everyday so need to slove this asap. Thanks.


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## WaterWheels (Aug 14, 2005)

As I said, I have never done this on a vehicle with a bad circuit boaed and can't say if it would help any. To be truthful I really doubt it will stop the buzzer as what you do is trick the warning system into thinking the sensors are working correctly. If a car has good sensors, switches really, and good wiring and the circuit is defective doing this really does nothing I think as the falt is in the circuit board. But if you want to try it I'll explain:
*Low pressure switch* - This switch is normally closed, that is when at rest the contacts in the switch anr touching and power flows through it to complete a circuit. That is why when the key is turned on but the engine is not yet started the oil light comes on. As soon as the engine starts and oil pressure builds the light goes out because the switch, about 0.3bar, is forced open breaking the flow to ground. So this wire is removed from the switch (located on the side of the cylinder head) and left in a way that it touches no metal.
*High pressure switch* - This switch is a normally open switch, that is when at rest the contacts inside do not tough (the circuit is broken). With the engine running above idle the pressure builds and closes this switch. The switch has an operation setting of about 1.8bar and the warning circuit board is set to require this switch be closed when the engine is at 2000RPM or higher. So the wire from this switch, located on the oil filter mount, needs to be removed and connected to a ground so the circuit board always reads it as "switch closed".

But like I said, if the falt is in the warning circuit board I really doubt this will have an effect.


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## dkfackler (Feb 8, 2010)

Not meaning to hijack the thread, but:

Wheels, where is the dynamic oil pressure warning module located? Bentley's diagram shows a current track to a module, but no clue as to location of said module.

I run a mech gauge as well, but like things to work, so would appreciate any guidance.

To the original poster, here in northern IL, I do as Fat Rabbit; 10W40 in winter and 20W50 in summer.


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## WaterWheels (Aug 14, 2005)

As for the where is it located, go back up and read Fat Rabbit's first post here. If you use a mechanical gauge and still want the factory warning system you need to use a "T" fitting so the mechanical can get it's oil and the switch can read the presure too.


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## Fat Rabbit (Nov 18, 2001)

As Water Wheels says the high pressure switch is located on the oil filter flange. I have run across many VWs with that wire disconnected from the switch and run to ground. I've done it myself, in fact, until I could get the system fixed. I recall one distributor that had a convienent spade terminal (Originally for the distributor metal shield that is almost always removed.) to connect to for ground. Ground that wire and see if that fixes the buzz. I have never run into cars with the cylinder head switch disconnected to disable the system.

However, over the years I have come to find that the buzzer issue usually involves oil weight. Resolving that issue is easy and leaves the oil warning system intact for the day it might be needed. 

dkfackler -- The "system" is located in the cluster as I explained above. You need to remove the cluster to access it. It's basically a simple job but does take some time. FR


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## dkfackler (Feb 8, 2010)

Hmm. Sorry, FR, I was reading too fast and missed that.


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## Fat Rabbit (Nov 18, 2001)

Here is a picture of the Oil Warning PC Board located behind the speedometer in the cluster. FR


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