1991 740 Wagon
2.3 I4 with turbocharger and an intercooler.

Hi,
My rear taillamp brake lights do not come on.

Of the 4 red lights on both taillamp cluster, only bottom two red lights stay on when I turn on the head lights. When I step on brake pedal with both headlights on or off, all 4 read lights do not come on.
I only get the middle small red light on. (which probably means the brake light switch on the pedal is fine.) I do have the lamp malfunction warning on when I turn on the headlamp or signal lights on.

I changed the lamp malfunction relay (big red cylinder) but things are the same. Found the bottom right red light had one of its filament broken so replaced the bulb but things are still the same.

I need to fix this to avoid paying for the fix ticket in about ten days so your help is much appreciated.

 

I would remove the connector at each light housing and using a test light or meter check for voltage at each pin with the brakes on and then again with the light switch on. If you have power then the problem lies in either the flex circuit or it's ground. Do your directionals work?

 

Yeah, my directions do work. I forgot to mention that when I turn on the fog light switch the reverse lights, right directional light and all four red lights do come on. Really confuses me.

 

Try jumpering the brake light switch . Take the switch out of the circuit.

 

Thanks!
But when I press the brake pedal, the middle brake light do come on. Doesn't this mean the brake pedal is ok?

How do I jumper the brake light switch?

 

Do you mean the third brake light above the back door comes on? To jumper out the brake switch just pull the 2 wires on the switch and either make a jumper with 2 male ends or use a heavy paper clip to join them together. This should allow you to see if you have voltage at the brake housing connectors. If you have voltage at the connectors and no lights then there is a problem with the housing circuit. If no voltage then there is a wiring problem from the brake switch to the lights. This will be more difficult. By the way did you do anything to the car and all of the sudden this happened? Also do we ASSUME you checked all of the fuses?

 

Yes, third brake do come on while other two don't. I will try to jumper the switch. I didn't do anything to the car but the bulb malfunction switch was on for a month and half and I didn't do anything to it until I got the fixit ticket and the reason was that one of the lower brake light had one of its two fuses blown.

 

So did you replace the fuses and have they blown again?

 

I'm so sorry. I wanted to tell you that one of the two filament in a bulb of right lower brake light was blown and was left like that for two months which cause bulb malfunction warning light to come one and stay. Not the fuse LOL.

 

OK do you have 12V at the connector to the brake light housing? Did you measure it?

 

Thank you very much! By playing with the wire connectors on the tail lamp assembly, I was able to fix the brake lamps. They come on when the headlight is not turned on. But when the headlight is on, both brake lights do not come on regardless of the brake pedal. So I have to turn the fog lamp on.

 

I had a problem alot like yours my brake lights stopped working changes the bulbs tested the wires, turned the fog lights on and they would work and it did end up being the fuses blew on mine, so might be worth another look if you get to frustrated. Good luck