taillight/brake/turn signal not working after installing aftermarket lights to a utility rack?

1995 CHEVROLET SILVERADO
133,581 MILES • 5.7L • V8 • 2WD • AUTOMATIC
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GHARLAN
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I added some aftermarket lights to a utility rack I installed on the truck as the rack covers the third brake light. The new lights also function as running and signal lights. I tapped into the wires of the driver's side and both the factory and new lights worked fine. I did the same procedure on the passenger side and now the new light on driver side works but not the original. With the switch on, I have one running light which is the new light, nothing on the passenger side. New light signal and brake work on driver side but not original light. Passenger side original and new lights both not working. Test light on the harness indicates power to lights is working, running, signal, and brake.
Aug 19, 2024 at 2:06 AM
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STRAILER
  • Experienced Mechanic
  • 55,233 POSTS
If the power to lights is working, running, signal, and brake then it sounds like the ground circuit to the rack is not working or you have something not connected correctly. Here is a guide to help you check the grounds and the exterior light wiring diagrams so you can see how the system works and where to test.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Also, check the parking light fuse, turn bk-up fuse and the stop hazard fuse. Make sure they have power. This guide may help as well:

https://www.2carpros.com/articles/no-tail-lights-exterior-running-lights-tail-lights-out


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Aug 19, 2024 at 11:42 AM
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GHARLAN
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My apologies for the delayed response, been on vacation. I have checked all that you suggested and is fine. Thank you for the diagrams, I have downloaded them for reference. Also managed to aquire a Chilton manual while on vacation.
Sep 1, 2024 at 10:48 PM
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STRAILER
  • Experienced Mechanic
  • 55,233 POSTS
No problem, I would use a test light on the power feed wires to see where you are losing it. There must be some bad connections and the test light will help if find where the problem is.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Please upload pictures or videos in your response of any problems so we can see what to help you with..
Sep 2, 2024 at 3:51 AM
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