I just had my 96 3.8L engine rebuilt and finally got the whole car put back together, but the temp gauge is not working! Coolant does not appear to be flowing either. I thought it was the coolant temp sending unit (under throttle body), but I just replaced that and I still cant get the gauge to twitch. Now I'm not sure how long to leave it running because there's no way to tell if it's overheating.
I can only guess it's something in the wiring between the temp unit and the gauge cluster, but not sure how to test all that exactly. SUGGESTIONS???

 

Take it back to the shop that did the work, or was it done by you?