Trailer Wiring

'03 Siverado 2500 HD 6.0L Trailer towing package. The right trailer brake light doesn't work sometimes. This then allows my electronic brake actuator to go off line. I have tested wires all along the truck wiring up to the cab and the right trailer brake light is out all the way up. Fuses are all good and and it does not matter what trailer we tow. Is there a connection or harness under the hood to check???

I HAVE THE SAME PROBLEM. 2003 2500HD WITH DURAMAX. RIGHT BRAKE LIGHT ON TRAILER WORKS SELDOM, BUT TURN SIGNALS AND FLASHERS ALWAYS WORK,(SAME LIGHTS AND WIRES.PLEASE EMAIL ME IF YOU FIGURE IT OUT . THANKS.
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