.........I'm trying to figure out why my Temp guage isn't working. As in, does nothing. '73 Roadrunner, Rally gauges.......on 2nd sending unit.......fuel/oil pressure work fine, and the lead to the temp sender pulses........what should happen if I ground the test light to that, instead of a body ground? My engine ground is good........but I haven't actually tried hooking to the sender. Before I put the dash in, I checked the gauges with a small battery (from a post here) and they all worked. I didn't use any sealer, and the threads were clean on both it and the block. Maybe another bum unit? I want to fix it soon, it is the only thing left not working. Even the stupid seat belt buzzer works!

When you ground the sender lead to the block what does the gauge show? Might run a jumper from the downstream side of the temp gauge directly to the block sending unit and check for a bad connection on the printed circuit copper strip (the strip for the temp gauge). EDIT with your VOM check for continuity between the sender body and the block

if the end pulses and you ground it, and the gauge moves, then I would say another bad sender.

Ok thanks, I will try these.

Well, when I turn the key on now the oil/gas gauges are still working, but there is no pulse at the temp sender. It was pulsing the last time I fiddled with it. What should I play with now?

Wiggle the wires at the bulkhead plug and see if it starts flashing.