[SilverMiner]

An update to close this thread -

The headlight switch was not the source of the drain. Also as a note to others who may read this in the future, I was wrong to think the AC duct below the steering wheel required removal. Simply unscrewing and moving the lower left dash vent allowed access to the headlight knob button.

I now believe the drain is due to the door switches for the interior lights although I can't prove it conclusively. The switches appear to be in poor condition or I'd test to see if removing them solves the problem. The measured drain changes slightly as I repeatedly open and close the doors. I was able to get the drain dropped to below 0.50 amps (how? don't know - magic maybe), which shouldn't be enough to kill a good battery just overnight. I'm running a Hellroaring dual battery setup that allows me to "self jump" so until the weather improves and new switches arrive I may just live with the situation.