1996 Other Jeep Models Voltage Indicator drops to zero

I have a 96 Grand Cherokee and recently the voltage indicator dial will be displaying ~14 volts while driving, then drop to zero, also triggering the "check engine" light. It reads zero until the engine is shut off and restarted. This occurs about 50% of the time. Also, I've been getting a "read lamp failure" warning, however all the lamps seem to be working properly. Thank you!