1991 Chevy Beretta ignition coil packs

To check if a DIS module and its crankshaft sensor circuit are working: connect a halogen headlamp to the spade terminals that mate the DIS module to the coils. A headlamp is recommended here because it puts more of a load on the module than a test lamp. If the headlamp flashes when the engine is cranked, the DIS module and crankshaft position sensor circuit are functioning. Therefore, the problem is in the coils.

If the headlamp does not flash, or there is no voltage to the module or coil pack when the engine is cranked, the problem is most likely in the crankshaft sensor circuit. On most vehicles, a bad crank position sensor will usually set a fault code, so use a scan tool to check for a code. Or, check the crank sensor itself.