Jim85IROC

My 3rd brake light doesn't work on my 91. It's not just a bulb :cry

When I test it with a digital multimeter, it's about 1 volt below battery voltage. When I use a test light (i.e. put a load on it) it barely illuminates. The brake light bulb won't illuminate at all. The ground is ok, it's the power line. I tested the wire a couple inches above the spot where it's crimped to the metal terminal, and it does the same. So... where does the green +12 volt brake light wire come from? I'm assuming that from the switch on the brake pedal, it goes into some box out of which comes the wires for the tail lights and the 3rd brake light. Am I on the right track so far? Where should I be looking for this stuff? Does somebody with a helm manual feel generous enough to scan in the pages that show the brake wiring schematics?

GusBustamanteJr

The 91 3rd light is independent of the tail and brake lights. It runs off its one leads from the brake pedal. Mine has the same problem, but I dont feel like getting under the dash to fix it!!!

vader86

I know that on my 86 there is a switch at the pedal close to the column. There are two connections to it, one goes to the rear lights, another to the 3rd light. Its possible that the switch itself may be bad. The wire goes to the ABS and then up to the lamps.

If you ran a search on recent topics by me on this, youd see some schematics, assuming that the 91 is the same or pretty close. I have yet to track down the problem with mine.

Jim85IROC

Thanks for the info. Maybe i'll get lucky and it's an independant switch on the brake pedal that's malfunctioning. If not, I might have to rig up some half-arsed relay setup to get a sticker. I just bought the car and I've only got 7 or 14 days to get a sticker.

jfb

The brake pedal switch is a double pole single throw switch with the poles internally connected. On my 87, the brown wire from this switch (the poles)goes to the 20 A stop/haz fuse. The white wire goes to the turn/haz switch assembly in the steering column and from there through a yellow wire to the left stoplight and a dark green wire to the right stoplight. The light blue wire out of the brake switch goes to the top brake light. If the contacts in the brake switch are worn, or if there is a resistance connection in the switch socket, firewall connector, or the top stoplight connector, then 12v won't fully be available for the stoplight. Connect your test light after each connection from the switch to the stoplight and you will find where the resistance connection occurs. That is: put your test light and voltmeter on the switch connector , then on the firewall connector, then on the stoplight connector (you have already done this).

jimswhite92

IM me a fax # and I will fax schematic to you.

Jim

Jim85IROC

Jim, you can fax me at 413-664-6336. I appreciate it!

I also appreciate everybody elses help. I'll be checking the switch on the brake pedal tonight. I sure hope that's it, because the wiring in this car looks brand new and it's going to burn me if I have to rip the car apart to track down a wiring problem.