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Old 05-23-2022, 09:34 AM   #13
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Originally Posted by bigdog View Post
I think I may have stated my problem a little hastily, and somewhat (VERY) embarrassed When I tested the lights in the beginning, I just connected the wiring harness from trailer to the truck, I never had the trailer hitch connected to the truck hitch ball as if I was towing.

In your Post you stated 'I have seen wiring set up that relies on the trailer ball to provide continuity for the ground', this may be the reason?
Going to actually attach trailer to truck hitch/ball and see if it resolves my issue. If it does, I feel like such a dumby !

Will report back with results....
REREAD 8gv's quote. "I have NOT seen seen a trailer wiring set up that relies on the trailer ball to provide continuity for the ground."

The continuity does NOT rely on the hitch connection. The WHITE wire is grounded to the trailer frame on the trailer side and to the truck frame on the truck side. When you connect the two connectors (truck WHITE TO trailer WHITE) it creates continuity between the two frames.

In fact, if hooking up the trailer "fixes" the lights, it simply exposes the real problem, that one of the WHITE grounds are no longer properly connected at the frame (corrosion/wear/broken wire).

HOWEVER, the ground is NOT your problem. If you have a bad ground, NONE of the lights will work. You have some lights working therefore the ground is working. (Unless the lights are working but dim. That would indicate that the current is grounding through a secondary (poor) path)

I suspect you may have a couple problems. One, a broken connection to your TAIL LIGHTS which also supply the side markers and license plate light. If the back tail lights are working, it is the specific feed wire to the side markers and license light OR corrosion/wear at some point in the loop that is blocking the current.

Two, the flickering could be loose connections at various places along the way, including the ground wire. The first place to check would be the actual car to trailer connecters. Are they clean and fitting well/snugly?
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