if you have a stability control system on your car its a part of the brake electronics, so it reads the the brake light switch state. so if there is a problem on the circuit then i can trip the stability control system. if this happens the car sees reading that dont make sense to it so it is trying to bring the car back under control and will cause "drivablity" issues because it thinks that the car is loosing traction and out of control. so depending on the system it can apply braking(not on all systems) reduce engine power and activate traction control.

 

Where do I find this step by step instruction for the brake switch?

 

For those of you who have the manual transmission, wait till the clutch switch goes out. You will loose the cruise, and your engine will start racing some when shifting making smooth shifts a real challenge.

 

I am extremely bummed. My battery was dead, and when I jump started it, I had the ABS light, stability light, check engine light. and the sluggish acceleration as described in this thread. I bought a new brake light switch and installed it while being eaten alive by mosquitos. It didn't fix anything. What next? TIA

BTW, 2001 A6 2.7T, auto.