I thought of that and disconnected each gauge, one at a time to test. No difference for each one. The only one I was not able to test (I think) is alternator (generator) gauge. I unplugged the plastic connector from the back of the alternator, but did not unbolt the hot wire. should I try that?

Also, the black wire with white stripe that runs through the alternator harness is not hooked to anything as I could not figure out where it went. (EDIT: Idle stop solenoid. My car does not appear to need one)

I'll try the swap again, but already did that once.

EDIT: NO DIFFERENCE.