I think I smoked a amp gauge!
CHECK THE BULKHEAD CONNECTOR!!!!!!!!!!!!!!!!!!
This is where 75% of old Mopar electrical issue evolve from. I'll talking about where the outside harnesses connect to the inside harness at the firewall behind the drivers side valve cover. Most of the time water, dirt, and other crap corroded the terminals causing high resistence which in turn creates heat, which leads to things either loosening up, or flat-out frying.... If you check for continuity it'll appear to be OK. Under load, well, that's a different story.
The MadElectrical link is priceless. There's very good information in it.