Ignition Control Module Input Test
- Turn ignition off. Remove distributor cap and rotor. Disconnect Yellow/Green, Black/Yellow, White/Black, and Blue wires from Ignition Control Module (ICM). See Figure. Turn ignition on. Check for battery voltage between ICM Black/Yellow wire and ground. If battery voltage exists, go to next step. If battery voltage does not exist, check for an open in Black/Yellow wire between ignition switch and ignitor wiring harness connector.
- Turn ignition on. Check for battery voltage between ICM White/Black wire and ground. If battery voltage exists, go to next step. If battery voltage does not exist, check for an open in White/Black wire between ICM and ignition coil, and check coil. If White/Black wire is okay, substitute a known-good ignition coil.
- Turn ignition off. Disconnect PCM 32-pin harness connector. Check for continuity in Yellow/Green wire between PCM harness connector and ICM. If continuity exists, go to next step. If continuity does not exist, repair open in Yellow/Green wire.
- Check for continuity between Yellow/Green wire and ground. If continuity does not exist, go to next step. If continuity exists, repair short to ground in Yellow/Green wire.
- Connect PCM 32-pin harness connector. Disconnect instrument cluster 22-pin harness connector. Check for continuity in Blue wire between ICM and tachometer. If continuity exists, go to next step. If continuity does not exist, repair open in Blue wire.
- Check for continuity between Blue wire and ground. If continuity exists, repair short to ground. If continuity does not exist, wiring is okay. Replace ICM.