1991 Chevrolet Suburban brake lights

JKEITH791

MEMBER
1991 CHEVROLET SUBURBAN
5.7L
V8
2WD
AUTOMATIC
149,341 MILES

I just bought this truck and at first the brake lights and turn signals did not come on at all but when I turned the lights on the left would light up as normal and the right would light up as if the brake was on. I found a cut wire under the passenger side and reconnected it. Then I noticed the drivers side bulb was not in all the way. Found the passenger side bulb was in backwards. So now I have everything working but the brake lights. I read that if the turn signals are working then it would indicate either a bad switch on the brake light arm or a bad relay in theengine compartment. Are there any other possibilities I should check for before replacing those? Im on an extrememly tight budget so id rather not blow alot of money on troubleshooting if I can help it. Thanks

Sunday, February 22nd, 2015 AT 2:02 PM

1 Reply

CARADIODOC

MECHANIC
34,331 POSTS

The best way to blow a lot of money is by replacing random parts. It doesn't cost you anything to diagnose the cause of the problem, THEN replace parts if necessary. In this case, you already found multiple causes and that didn't cost you anything. Next, since the brake light switch does sound like a good suspect, measure the voltages on its wires. You may have multiple switches built into the assembly, and more than two wires, but if the wire colors are the same as in previous years, you want to look at the orange wire and the white wire. The orange one should have 12 volts all the time, and the white one should have 12 volts when you press the brake pedal. If the voltage is missing on the white wire, replace the switch. If voltage is missing on the orange wire, suspect a blown fuse.

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Sunday, February 22nd, 2015 AT 3:23 PM