Rear brake lights not working, but third (CAB) brake light is

SWITCHBAK

MEMBER
CHEVROLET SILVERADO

Never had any problems with it until recently when the rear brake lights stopped working while the third brake light is fine. The fuse in the dash is good, the bulbs are good. Replaced fuse and bulbs anyways and still have the problem. Anyone have any ideas of what would cause this? Flashers, signal lights, tail lights, and reverse lights all work.

3 Replies

MIKE H R

MECHANIC
3,094 POSTS

Check the connections at the brake light switch use a static tester to make sure you have voltage going out. The two brake lights the cab and the regular rake light are on diferent fuses. If they are all right check with a tester if you are getting voltage to the rear stop lights at the sockets.

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Friday, February 26th, 2021 AT 10:51 AM

SWITCHBAK

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Ok. I checked the connections at the brake pedel. There are 6 wires there. Five had power (12 volts) when I didn't press the pedel and 1 had power only when I pressed the pedel. And I also verified that the fuses are good again. Here's the weird part. I tested power at the rear stop light sockets I had no power when I wasn't pressing the brake, but when I pressed the brake I would get a very small reading. Like 1 volt or so. That doesn't seem right to me. Shouldn't there be the full 12 volts or something?

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Friday, February 26th, 2021 AT 10:51 AM

SWITCHBAK

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3 POSTS

I ended up taking it to the shop. They said it was both bulbs that were bad. I'm just not to sure of that cause I know I checked them with new ones and didn't have any lights still. They also said that they had 12 volts to the sockets where as I only got about 1. Not sure what changed with that but they got it working. :D thanks for the help m_j_ritzel. I really appreciate it.

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Friday, February 26th, 2021 AT 10:51 AM