temperature gauge

[wolfords]

Hello all, My temp gauge has given out on me and Im not sure were to start looking. I was in the process of flushing the coolant and realized the gauge would only get about a quarter of the way up. Now it wont budge at all. The fan is still kicking on, but its very disturbing to see no reading, especially since its been 100 degrees every day. Any suggestions on what could be wrong?
Thanks
Scott

[anjum]

Probably temperature sender unit, the one at the front of the head with the single wire plugged/ clipped on to it. To test the gauge take the wire off and the gauge should drop to zero, touch it to earth/ engine and it should go full scale.

[wolfords]

I just unclipped that wire. with it off, the gauge shows nothing. With it grounded, it also shows nothing. does that mean the sensor is bad?

[Geoff Weeks]

Nope, either the wireing or the gauge head itself. More testing is needed. ground the sensor wire at the dash board to tell which it is.

[peva]

Geoff's right. This tells you nothing about the sender. The fault probably lies in the wiring or the gauge itself. If you can get to the connections behind the dash through the speaker grill, ground the earth there. Make sure it's the right one and not live. Use a DVM if unsure.

PS Before you do anything else, make sure that the connector clip on the sensor end of the wire has connection to the wire itself and if necessary remake it. It may just be faulty here. It does get hot and degrade over time.