Engine/Transmission (1994 - 1998) no tach and no charging

[amos_eva]

On our 95 2500, the tachometer gauge (drops to zero) and battery charging (indicated by less than 14 volts on voltmeter) stop functioning simultaneously. One time they functioned normally for a few minutes at idle and another time they functioned normally for 8 miles but again failed when idling. We checked the battery and alternator connections. We're guessing it's the PCM since it sends signal to the tach and controls voltage regulation. Does anyone have any ideas? HELP



Amos and Eva





2wd; 120,000 miles; automatic