[davepl]

Is this perhaps the 4-beam GMC headlight harness from LMC? If so, it's wired all wrong and has been for years and if they're still selling it that way I'm shocked and dismayed but I guess not surprised.

Long run of yellow insulation across the rad support? That one?

If so, I had to start from scratch re-pinning all of the headlights and got it to work. There's enough wire and connectors and relays in there to build it properly. Just takes a lot of time and testing.