Ford Repair: Temperature Gauge malfunction, coolant system, temperature gauge

Question
Hi,  I just swapped out the intake manifold on my 1996 Ford Mustang GT 4.6L SOHC engine as the old one had cracked and was spewing coolant.  After reassembly and refill of the coolant system, I started to test drive the car and noticed that the temperature gauge read beyond max to the hot side.  This was while the engine was cold, hot, or stopped with the neg battery terminal disconnected.  Do I need to replace the temp gauge or is there a way to reset it?  Thanks for your help.  Ray

Answer
Hello and thanks for the question...I'll try to help.
It would seem that one of two things has happened.
1. you got the wire pinched for the sending unit and it is grounded.
2. The sending unit is faulty.
I would suggest that you look at the wiring and then, if nothing is found replace the sending unit.
Hope this helps,
Erik