First post...hope you guys can help out.


New owner of a 2004 911 Cab with triptronic.


I'm having a problem and think the headlight switch or brake switch is at fault...but not sure.

When the headlights are turned off, my brake lights function normally and I don't get the PSM/ABS warning lights on the dash.


When the headlights are turned on, the brake lights do not turn on when I press the pedal and the ABS/PCM warning lights come on.

Would a faulty brake switch be the cause of this or could it be something else? I don't have a manual to look at the wiring schematics, so I don't know if the brake light power passes through the headlight switch at all.


At night, what tail lights should be visible? I only see the square one on the inside on the light cluster. Should the outside light be on as well?

Turn signals do function as expected.

 

Usual cause of this malady is the brake light switch.