I installed a ss dash and gauges in my 71 chevelle along with a new dash harness. When I hooked up everything it all worked but the temp gauge. I installed a new temp sending unit in the block and hooked the wire up to it but my red arrow in the gauge just points way past the 250 mark and just stays there. Like I said the tach, clock , and fuel gauge all work fine. Before I hooked the wire up to the sending unit the arrow was all the way to the left on the gauge. Any body got any ideas. Thanks Harryschevelle

Do you have the right sending unit? There is one for idiot lights and one for gauges. It seems like it's working just with the wrong sensor.

I think I have the right sending unit. I ordered it for the dash with gauges. I guess I could have gotten a bad one. I may have a old one from a prevouis car I will screw it in and see what happens. Thanks for the response. Harry

If you remove the wire from sending unit, with key on, what does gauge do?

Bad ground possibly????

If I remove sending unit wire with the key on nothing happens the arrow just stays there past the 250 mark. Harry

Ok. That means your problem has nothing to do with sending unit. Either the sender wire is getting ground from somewhere else or the gauge is not grounded.

Possible places the sender wire is getting ground is at the firewall bulkhead, or at the PCB connector.

Check the ground at the gauge, The top post of the gauge should have a good connection to the resistor, the bottom post should also have a good connection to the resistor and ground, cluster metal back. The cluster metal back also needs to have a good ground.