JoePatch

I have a issue with a 2003 A8 that is kind of different.

The symtoms are:

When the headlights are off:

Light warning/ warning chime when I push the brake pedal.

Goes away after brakes are released. I did notice that the front running lights glow brigter when I push the pedal.


When the Headlights are on:

Unhappy Triad Condition - BRAKE LIGHT / EBS / ABS

Goes away after you restart the vehicle with the headlights out.

I think also that the Brake lights are dimmer than normal.


The Ross diagnostic tool reads a Brake Light Switch code, but drilling down deeper, I can see both poles of the switch "pulling in" when I press the pedal


This sounds like a bad ground to me. Does that make sense?

Has anyone seen this one?

Does anyone know Where physically the lighting system grounded in this car?

Can this be caused by bad lamp connection(s) ?



Thanks for your help!!!

Joe

Mister Bally

Sounds like a massive ground fault as well. The harness on these cars are pretty good (assuming you have a D3, not a D2 since you say 2003. Model Year 2004 was first year for D3 in the US.

An official service manual is mandatory for these cars IMO. I believe grounds meet near the headlight assemblies.

That said, the brake light switches fail often on these cars.

JoePatch

Thanks for your input! Can I tell if this is a D3 by the VIN?

mishar

That ground connection is probably one on the left A pillar, next to the dead pedal.

mishar

Google D3 and D2 pictures.