Drivers-side rear brake light

[MaxBell]

On my 1987 325i, my left (drivers-side) rear taillight doesn't come on when you push down the brake pedal. It is showing up in the OBC, but the bulb is fine. I've looked at all the fuses and they're all fine.

The other taillight is fine, as is the third brake light.

I have searched the internet to no avail, if anyone knows where I can look, I'd appreciate it.

Thanks.

[Mo Brighta]

You say the OBC says it is out, I assume you looked and it does not light. Cold be several things.

If all other lights on the left work as usual, you have a good ground. If they are dimmer than the right side, could be a bad or weak ground.

If the bulb is good, I assume you tested it in another location. Of course it has a silver color base, not brass. If it is brass, toss it and replace it with a silver (actually nickel plated) base bulb.

Your lights have a metal strip that holds and grounds all bulbs so the positive (+12V) contact is the only unknown. Installing bulbs is a 'push and turn' thing, and the springy tab that powers it should push back to give good electrical contact.

If it goes in the socket easily and wobbles a bit, could be the contact is losing it's springy force against the bulb. You should feel a distinct spring pressure against the bulb when putting it in the socket. If not, take out the bulb, and pull up on the contact towards the bulb to increase force, then try again.

Good luck, let us know how loose it seems when you check the bulb.

And if you want to swap it out for better and brighter and bigger rear lights, let me know.

Happy new year!