Temp gauge issues

Hello fellow FABO people I have a 1974 Dodge Dart swinger and I am having a problem with the temp gauge reading way past overheating even when the motor is dead cold I had the gauge cluster out today and checked to make sure is it connected to the cluster correct and clean and it was so I am asking is there anyway to fix this before I have to cough up the 130 bucks to classic industries thanks for your time