Rear Exterior Light Issue

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97C1500TJ

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Hello,

I hope this is in the right section as this is my first thread. I am having weird issues with my taillights on my 1997 C1500 and have no idea where to go next. I’ve checked all fuses under the hood and by the dash. I have not checked the relays nor do I know how to. I originally thought it was just the left side socket as my blinker was my only issue. Now it’s progressed to the following:

Headlights OFF: Reverse lights do not come on. Instead my brake lights come on when I’m in reverse. Left brake light and blinker do not work.

Headlights ON: No taillights, brake lights, or reverse lights. Right blinker is brighter than the left.

Any help is appreciated. Thanks
 

someotherguy

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Probably a bad ground. It could be one or both of the taillight circuit boards are bad (fairly common once they get old) or simply the ground wire for the rear lamp harness is bad. If you have a trailer harness attached, disconnect it for now until you have the lights working correctly.

If you look at the end of the driver's side frame rail where the bumper bracket bolts up, you'll find a disconnect for the rear light harness. The rear section will have a ground wire going to either the frame, or one of the crossmembers near the rear of the truck. Be sure it's attached and in good shape.

You can disconnect the rear lamp harness and test with a simple test light right there where the harness comes from the front of the truck. Ground your test light right there at the back of the truck and then probe the connector. Yellow is left turn signal/brake light, dark green is right turn signal/brake light, light green is reverse lights, brown is taillights/tag lights.

Richard
 

97C1500TJ

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Probably a bad ground. It could be one or both of the taillight circuit boards are bad (fairly common once they get old) or simply the ground wire for the rear lamp harness is bad. If you have a trailer harness attached, disconnect it for now until you have the lights working correctly.

If you look at the end of the driver's side frame rail where the bumper bracket bolts up, you'll find a disconnect for the rear light harness. The rear section will have a ground wire going to either the frame, or one of the crossmembers near the rear of the truck. Be sure it's attached and in good shape.

You can disconnect the rear lamp harness and test with a simple test light right there where the harness comes from the front of the truck. Ground your test light right there at the back of the truck and then probe the connector. Yellow is left turn signal/brake light, dark green is right turn signal/brake light, light green is reverse lights, brown is taillights/tag lights.

Richard
Thanks. I will give that a try. I did replace one of the taillight circuit boards already and the problem persisted so I went back to my original. Maybe it could be the other one.
 

Chevy797

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Yes it did. I do have a problem currently where if it rains, my left blinker goes out until it dries. I guess I should try some dielectric grease or something.

Ok im gnna try it to reconnect my ground again. Right now I'm im having an issue with both of my reverse lights flashing with my right blinker and also coming on everytime I hit my brake i just removed the brake controller and trailer wires but still same problem.
 
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