David Ebby

I have now moved on to trying to fix another problem. The in-dash temp. guage is inoperative. The needle is out of view and can only be seen by looking from the side using a flashlight. I identifed the sending unit and removed its single wire and grounded the wire, turned on the key and the guage did not move at all. On most cars this should give you a full deflection of the needle???? right! To me, it means that the guage itself is bad or the wire going from the sender to the guage is bad! Any suggestions?

lxman1

You are on the right track. It should go to the high side when grounding the sending unit wire.
Could be a bad connection at the plug on the back of the cluster or just a bad gauge.

Turbo4banger

I have the same problem in my 88GT vert, and checked voltage from the wire at the sending unit and got voltage (3.?V) I think. I have replaced the sending unit but still no luck. I am wondering if anyone knows the correct voltage?

I have 3 clusters that I use for parts and 2 of them have known working water temp gauges and I still have no luck. But with voltage, known good clusters and spare sending units, I am not sure what else to check.