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Discussion Starter · #1 ·
Hello everyone just joined today as a new member from Ohio. Hope to learn and help out with what I can in the future. Now to my problem. I recently purchased a new 16 Silverado 1500. Back in July I purchased a new 8.5 x 20 car hauler. At the time I had a 15 Colorado with the towing package. I inserted the plug into the trucks connector. It seemed to go in kinda stiff but had no problems with lights. In October I purchased the Silverado and was going to Charlotte NC for a car show. Before I left I hooked up trailer to move it and had the fault on the DIC for system wiring. Took to dealer and they said trailer problem not truck. So I replaced the plug on trailer with the same way the wiring is on plug and now I have trailer lights but no left turn signal and no left brake light. When I cut the wires to replace plug I installed them in the same position so what gives? Jeff
 

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Use a volt meter to check voltage at each pin on the truck side. Do it with every function applied than off, one at a time so you know what pin does what. You may want to trace trailer wiring and make sure each pin on the trailer side goes where its suppose to. You can google a picture of a 7 pin plug to verify each pin on the truck side is where it belongs.
 

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So, are the left turn signal and brake light working on the truck when the trailer is plugged in? If the truck blinkers and tail lights work with the trailer plugged in, then go back to the trailer lights and check them for power at the light sockets. If you are getting power there, then it is the bulbs. If not, move up and check just before the wires enter the lights. If no power there, then move up to the front of the trailer and check the wiring there just before the plug. Then check before the plug. Once you finally find power along the system, you know the problem is between that point and back to the previous place you checked. It is just a matter of narrowing down further between those two points.
Keep in mind the trailer (Or Truck) could have had some customized trailer wiring done to it at some point.
 

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Had a similar issue, thought it was the truck harness, thought it was the trailer harness. I fudged up and forgot I smashed one of my trailer lights up and threw an old one one. Apparently you CANT mix trailer lights, specially the style with the built in license plate light. Swapped to a new set of lights, no more issues.
 

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Discussion Starter · #6 ·
Thanks everybody for answering to my problem. It was not the way I wired the plug but it was a blown fuse under the hood. Thanks wildchevy for the help I never gave it a thought about the fuses under the hood. Thanks again to everybody for your help.
 
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