Bstocky

yea I also followed that diagram and bought resistors off amazon. I tested another set of OE led tails from my buddy and they did the same thing, so I ordered a premade harness from the harness doctor and no issues since.

Whatharness are you running?

Hello, I have factory led tail lights on my 2015 Denali hd, wiring harness adapter in place. Have had them in for a few months now and just noticed tonight after the brake was applied for like 10-15 seconds or longer, when the brake was released the large C shape running light was barley on. The little side led in the tail light was illuminated normally, and after a few seconds the large C running light comes Back on. This seem like a internal tail light issue? thank you