View Full Version : Brake lights, DRL, blinkers and cruise control acting funny

11-25-2018, 06:36 AM
I am new to this forum and got a new to me 2001 A4 B5 Q. I have been doing some fixes here and there but I got to this point and would like to know if some one had this issues and found a solution.

Point 1
When turning on the DRL/headlights all 4 corners DRL lights and Headlights turn on OK. But also the 3rd brake light (on the rear windshield) turns on. And if I apply the brakes the brake tail lights go on/off as normal and the 3rd brake light goes brighter when brake is apply and dims down when brake is released.

Point 2
With the Headlights/DRL switch in the off position all lights are off as they should be but when I apply the brakes the front left DRL turns on along with the 3rd brake light and brake tail lights.

Point 3
Hazard lights they work as they should be all the time. But blinkers both (right and left) 10% of the time works OK and 90% just blinks once and they stay off.

Point 4
I notice the Cruise Control can be activated only if the Headlights/DRL switch in the off position. If I have the CC ON and then I turn on the headlights/DRL the CC deactivates and I can not reactivated until I turn off the headlights/DRL.

Does the hazard lights switch relay (PN 8D0941509H01C) does controls the brake circuit too?

I have seen a few post and I am aiming to replace both the brake switch and the hazard lights relay.

I appreciate if any of you may know where the problem can be.