Corolla electrial problem

This is a strange one.
My corolla uses a combination 21w/5w brake light bulb in rear cluster. It is on with normal lights and gets brighter when i brake. the bulb on one side has started to stay on the bright setting all the time, the 21w setting, even when im not braking. It only comes on like this when the lights are on or i brake so it is not the brake pedal sensor and the bulb on the other side is working as normal.

I have replaced the bulb but same problem. The buzzer that comes on when you open the driver door with the lights left on has also started sounding if i have the brake pedal depressed(and no lights on), it started doing this when the rear bulb started staying on bright.

Any ideas? Relay? Switch maybe? I havent a clue!

The other side still gets brighter when i brake so i think it is relatively safe to drive at night but want to get it fixed asap! Thanks

PADRAIC.M

What year is it?

94 hatchback

PADRAIC.M

Sounds like the bulb holder- basically instead of the current flowing through the earth to ground it is going back through the taillight pin, either the bulb holder is bridging across the two pins or the earth (black/white wire) is corroded and not making good connection? Easy way to check is if you remove bulb on side effected does buzzer stop?

Thanks Padraic. That sounds very likely. i didnt consider that the holder could go bad. I will check today if the buzzer stops with bulb out and just brake pedal pressed. Thanks for the help.

It was indeed the bulb holder. Corrosion on the dual terminals was causing bridging. just cleaned them and fixed! Thanks Padraic

PADRAIC.M

No problem.