Not sure this applies, but I just helped a neighbor with an LED tail light on a minivan that was causing problems. Would not flash very brightly when turn signal was used or brake pedal pressed. Measured everything. Couldnt find it. I discovered we could take the entire assembly out, fiddle with it, and it would work for a bit. Turned out to be the assembly itself (the LED assembly) that had a crack I could barely see with a magnifying glass. But it was enough to reduce current flow. Thing looked normal with just tail lamp lit, but press the brake pedal and the whole thing dimmed rather than getting brighter. Replacing the LED assembly did the trick, even though it was still working.2008 Pantera Classic2014 Mercury Pro XS 200