[djcwardog]

I went ahead and swapped out my own fabbed harness with a plug and play version from the pros in Las Vegas! While they are still working to ensure that their sourced plugs mate precisely with the factory jacks in the LED Dimmer Switch and in the HUD Switch, the function is correct. Being an old-school retrofitter, I was able to use a belt sander and a razor blade to trim the LED plug in their harness a bit to fit. Interesting that the plug fit perfectly into the jack on their harness, but that same plug was too tall for the opening in the LED Dimmer Switch itself.

Having swapped over, I now believe that the fault in my own harness was an incomplete soldering of the two wires running into the ground wire leading into the cluster. Everything worked when I applied a bit of tension to that part of the harness so it was not an error in the wiring diagram itself.

Bottom line - a very nice upgrade when done along with the uplevel cluster. My insurance company says my car is an “LT1/1SS” so might as well get what I wanted from that trim level into my LT1 car!