Dodge Repair: 88 5.9L Ram: charging system

Question
I have a 1978 dodge ram power wagon with a 5.9 engine. 85,000 miles. I inherited this thing. problem I am having is the negative wire going to the gauge in the dash is getting hot. I changed the alternator. I am wondering if I need to change the regulator or sending unit if it has one. positive side works fine. any idea would help.

Answer
Hi Joe,
I don't have a wiring diagram so can't be specific about this problem.
I don't quite understand how the negative (grounding) wire for the dash gauge  is getting hot unless there is either:
too much current flowing through the gauge in the dash (in which case the positive wire would also be subject to heating unless it was a fatter wire) or the connection at either end of the negative wire were not clean and tight. How much current is showing on the gauge (or voltage if that is what it shows)?
I would check the negative wire for its connections, and if that doesn't solve it, then you could increase the size (thickness) of that wire.
Before changing the regulator it would be good to measure the voltage on the battery when the engine is running. Generally the voltage should be between 14 and 14.5 volts. If it is running higher than that then the regulator should be changed.
Roland