Brake Light Problem

guerito

I've got a 1998 Audi A3 1.6. The brake lights aren't working properly. When the headlights are switched off the brake lights don't come on at all. When the headlights are switched on the brake lights are on constantly. I've replaced the bulbs and fuses with no joy. I've seen a couple of threads here about the brake light switch being a possible cause of constantly-on brake lights, but I wanted to check if anyone knows whether the fact that they don't come on when the headlights are switched off might suggest an electrical fault?

I'd replace the brake light switch myself, but wouln't have a clue about the electrics. I'm not working at the mo, so the cheaper the solution the better, unfortunately .

Any help would be much appreciated.

peasant

I don't think that the brake switch is your problem.

Sounds like a bad earth or rotten contact to me. These can be buggers to locate and you'll probably need a car electrician to check it for you.

First make sure though that on the rear light cluster all cables are properly terminated, that there is no corossion and that all bulbs are properly seated and make good contact.

guerito

Thanks for the feedback, Peasant. I was hoping it wouldn't be the electrics. Oh well...

Mr.Diagnostic

Are you sure the brake lights don’t work as normal when the lights are switched off? With the lights off, ignition on, do the dash lights come on when you press the brake?

Check that there are no single filament bulbs in the rear light holders where there should be double ones.

crosstownk

Check that the brake light bulbs are correct. Pay particular attention to the offset of the locating pins on the side of the metal section of the bulbs. If these are wrong then it can cause feedback into other circuits. I've seen this quite a few times.