my friends got a 97 mach 1 and was trying to get his temp guage working. does anyone know if there were problems with these or is it probably just a bad connection, crimped wire, etc.....?is it usually at the guage or at the head?...does anyone know the resistance on the piece at the head?i dont know the name of it....are these a common prob?
any help would be appreciated.

Pull the wire off the sending unit (head) see if the guage works, if not ground the wire, see if guage works, if guage works grounded it is the sensor, if gounded or not grounded and guage still does not work it most likely is the guage itself or wiring. Also make sure the sled does not have a faulty thermostat, and try revving it up a little, some of them will not work at idle due to weak electrical output.

Had problems with my 97 and it was the wiring running underneath the pipes.had to fix in that area.Just another spot to check.Good luck.