Have a 1995 RAM 3500 diesal dually, had trouble starting and changed out the starter. Now, the gauges won't work, pre-heaters won't come on, NO A/C, alternator won't charge and air intake solenide won't energize on startup. Had the alternator tested it is ok. Could this be the computer, a ground? Please help.

 

Sure you did not leave a wire disconnected when you replaced the starter? Don't know on your model but some vehicles have a power pickup wire going from the solenoid. The same terminal that the positive wire from the battery connects to. If this wire is not connected nothing will work. Suggest you take a hard look around and see if there is perhaps a wire floating around doing nothing. How about on the battery? You must have disconnected it when you replaced the starter. Did you remove a wire at that time?
Let us know how you fixed the problem, even if your face is red.

 

The truck starts now, but these other issues have happened. Could it be the computer?

 

Nancy, the computer is the least likely problem. As Mexstan says check for a wire that didn't get replaced properly. Maybe it's the crank sensor (unlikely, it's at the front) but I think it sounds a lot like a ground or a feed wire that was either not hooked up or hooked to the wrong place.

I'm not a mechanic, but thats where I'd start.