Brake lights not working

  • 5.9L
  • V8
  • 161,221 MILES
Vehicle listed above, 5.9 R/T. At first, my passenger side brake light and front low beam headlight wouldn't work. Everything else worked fine; turn signals, hazards, running lights, fog lights, but no 3rd brake light. But the passenger headlight does work in high beam? So I replaced all the lights all the way around. Tail lights, marker lights and headlights. Now I don't have any brake lights at all on my tail end, but the 3rd eye light on my tailgate as I replaced those also. Also my turn signals don't work on the rear either but they do on front? None of things were happening until I changed all my lights? Please someone help? Any suggestions as I don't want to get rear ended! Thanks guys!
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have the same problem?
Friday, April 9th, 2021 AT 2:21 PM

1 Reply


If none of the rear lights are working, have you checked the fuses? Also, there is a parking light relay that should be checked.

I attached the entire wiring schematic for the exterior lighting system. I had to cut the pic in half to make them readable, but I did overlap them so you can follow them.

If you look at pic 3, I circled the grounds for the rear lights. Note they are the same ground, so something may have failed there.

If you look at pic 4, it shows the fuse box in the vehicle. I highlighted the fuse to check and the relay. When checking the fuse, make sure there is power to it as well. Also, if there is a relay with the same part number, switch them. If there isn't here is a link to check the relay:

Here is a link you may find helpful when checking power to the fuse:

The ground for the lights is on the left rear body of the vehicle.

I hope this helps. Let me know if you have other questions.

Take care,


See pics below.
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Friday, April 9th, 2021 AT 9:18 PM

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