Light problem baffling me

[scaramac]

I am having some wierd issues with the lights on my 2001 B6 A4 Quattro Sport. I changed my rear left brake light bulb last week, everything seemed to be working fine then at some point between last Thursday and Tuesday this week, and I don't know if these are related, but when my lights are on, my rear lights do come on but on the left hand side it is very dim and the left hand front headlight doesn't come on at all while the front left side light is on but also very dim.

Oddly, when I press on the brake pedal, the front sidelight and rear light are no longer dim, they become bright, and the brake light remains on even when i take my foot off the pedal, however the headlight on the front left remains off.

I dont know if anyone has dealt with this before? I am confused! I have looked at the wiring diagram and it seems to me that if it is affecting so many things on three different light clusters, then it may be something like the power control unit or a relay.

[mikeybutch]

Could be the brake pedal switch which seem to cause wierd problems when they fail and are an easy fix

[Alan02]

First, go back to the bulb you replaced for the Brake Lamp and check it is the correct type. Depending on your lamp, it could be a 12v 21/5W (double fillament, twin contacts at the base).If so, ensure you have it located in the holder correctly. They have off-set bayonet pins to locate bulb in holder. If you have fitted it wrong, you could have a back-feed to the other lamp circuit if contacts on the bulb are touching both spring contacts of the holder.

[Crasher]

My money is on Alan being correct in you having fitted the wrong type of bulb, I see this a lot. Twice last week...

[scaramac]

This forum never fails to amaze me. Once again a Mental problem sorted from experience. I changed the bulb for the double filament one and problem solved. Think the headlight may have been unrelated as I knocked the HID box a few times and the light is working again. Cheers for the info and the experience once again.

Kev