'75 with center console guages. Temp guage doesn't work. When ignition on, guage jumps off peg to bottom of temp scale on guage, but never moves from there. Guage has good ground and power. Temp sending unit? Is there a most problem-prone part of the oil temp guage system?

i'm going to go with there is SOMETHING that the sending unit is grounding out too....becuase that position is where the needle goes when there is *nothing* hooked in....BTDT. if the engine is cold, it moves a little further out. Try and see if your connections are good--if you need help pm me....i've put mine in, and all of my wires werent good at all--i had to cut them and everything.

I vote for broken or unplugged wire between the gauge and the sender. A grounded wire would send the gauge to max-hot position. (BTDT!)

It is possible for the sender to have failed with infinite (or near-infinite) resistance, but unlikely.

Unplug the wire from the "G" terminal on the back of the gauge. What's the resistance from there to ground? If it's infinite, you have a broken connection somewhere between there and the sender. Check the engine bay, over on the right side, just below (sometimes just above) the sheet metal--near where the throttle cable comes through the engine shelf. Should be a single-wire box connector with a green/black (I think, maybe green/red?) wire going to it and going from it.

--DD

thanks for clearing that up Dave........

Thanks guys. Got it fixed. The wire was broken.