Test A: No Communication With Instrument Cluster
NOTE:
Perform all voltage and resistance tests using a Digital Volt-Ohm Meter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.
- Turn ignition switch to LOCK position. Disconnect instrument cluster 20-pin harness connector C220b. See Fig 1. For instrument cluster and connector location, see Figure. It may be necessary to remove instrument cluster for access to connector. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Turn ignition switch to RUN position. Measure voltage between ground and instrument cluster harness connector C220b terminal No. 10 (Red/White wire). Voltage should be battery voltage. If voltage is as specified, go to next step. If battery voltage is not as specified, repair open circuit in Red/White wire between instrument cluster and fuse No. 21 (5-amp) in Battery Junction Box (BJB). BJB is located in engine compartment, near battery. For PASSIVE ANTI-THEFT SYSTEMS circuit identification, see WIRING DIAGRAMS . After repair, clear DTCs and repeat self-test.
- Leave ignition switch on RUN position. Measure voltage between ground and instrument cluster harness connector C220b terminal No. 11 (Pink/Black wire). Voltage should be battery voltage. If voltage is as specified, go to next step. If voltage is not as specified, repair open circuit in Pink/Black wire between instrument cluster and fuse No. 5 (15-amp) in Battery Junction Box (BJB). After repair, clear DTCs and repeat self-test.
- With ignition switch on RUN position. Measure voltage between ground and instrument cluster harness connector C220b terminal No. 12 (White/Light Blue wire). Voltage should be battery voltage. If voltage is as specified, go to next step. If battery voltage is not as specified, repair open circuit in White/Light Blue wire between instrument cluster and fuse No. 34 (20-amp) in Battery Junction Box (BJB). After repair, clear DTCs and repeat self-test.
- Turn ignition switch on LOCK position. Measure resistance between ground and instrument cluster harness connector C220b terminal No. 20 (Black/White wire). Resistance should be 5 ohms or less. If resistance is as specified, go to next step. If resistance is not as specified, repair open circuit in Black/White wire between instrument cluster and ground point G203. Ground point G203 is located behind center of instrument panel. See Figure. After repair, clear DTCs and repeat self-test.
- With ignition switch on LOCK position. Measure resistance between ground and instrument cluster harness connector C220b terminal No. 1 (Black wire). Resistance should be 5 ohms or less. If resistance is as specified, repair module communication concern. See MODULE COMMUNICATIONS NETWORK - MUSTANG article in ACCESSORIES & EQUIPMENT. If resistance is more than 5 ohms, repair open circuit in Black wire between instrument cluster and ground G203. After repair, clear DTCs and repeat self-test.