Voltmeter on dash reads no charge...but

[ibradley77]

My gauge on dash is showing no charge on my 77 chevy cheyene. But when I rev engine, the lights go brighter like the alternator is putting out a charge. Could it be an ext voltage regulator prob?...Noticed right before it happened, my gauge would either be at 0 charge, or peged on full charge, just below the red.

 

[dyeager535]

Voltage regulator isn't external on your truck.

Put a voltmeter to the battery while it's running and see what the voltage is. 13V+ you are fine, 12V+ with a full load at idle isn't too bad.