[deuce lover]

What glennpm said in post #4. I have worked on these gauges for yrs and use a 9V smoke detector batt with alligator clips attached to wires .That hold them secure to the batt terminals.I just touch those wire momentarily to the gauge lugs.If needle moves the gauge is good - to me.I reverse polarity if no movement .If still no movement I open up the gauge and do surgery.Most times that heating element wire is severed.Sometimes I am able to do a repair and sometimes not.