Weird problem. A4 B6 Cab highline.


Often when I brake I get an error in the dash regarding the auto lights sensor and the main headlights come on (can be a quick flash of the headlights or for as long as I keep the brake pedal pressed).


VCDS shows error that there is no signal from light sensor - intermittent.


Other symptoms include:

• Coming home light and auto light leds on light selector flicker at high rate (while brake pedal is pressed)
  
• Power to centre rearview mirror is lost (compass switches off)
  
• Have noise (static hiss) from speakers that goes away when brake pressed
  

Have replaced the power control module and the rearview mirror and all rear bulbs (apart from high brake light) and the brake pedal switch as well as checked the wiring.


Since replacing the rear view mirror it happens approx 30% of the time. With the old mirror it was happening 90% of the time. Also with new mirror when it happens it just flickers with the old sometimes it stayed on as long as the brake pedsl was depressed.


Btw, it only happens if light selector is in the off or in the auto position.


Finally (though could be unrelated) sometimes the horn sounds weak/"off tone".


Any ideas appreciated.


W.