Test H: Speedometer Inoperative
- Connect New Generation Star (NGS) or Worldwide Diagnostic System (WDS) tester to Data Link Connector (DLC). DLC is a 16-pin connector located below center of instrument panel. See Figure. Using NGS/WDS tester, observe GEM PID VSS_GEM while driving vehicle between 0-55 MPH (0-89 km/h). If PID VSS_GEM value agrees with speedometer, go to next step. If PID VSS_GEM value does not agree with speedometer, see appropriate ANTI-LOCK article in BRAKES.
- Turn ignition switch to LOCK position. Disconnect Central Junction Box (CJB) 34-pin harness connector C242B. Remove instrument cluster to gain access to instrument cluster harness connectors. See REMOVAL & INSTALLATION . Disconnect instrument cluster 16-pin harness connector C250B. Measure resistance of Gray/Black wire between CJB 34-pin harness connector C242B terminal No. 14 and instrument panel 16-pin harness connector C250B terminal No. 10. See Figure and Fig 1
. If resistance is 5 ohms or less, go to next step. If resistance is more than 5 ohms, repair open in Gray/Black wire between instrument cluster and CJB. See WIRING DIAGRAMS . Retest system operation.
- Measure resistance between ground and CJB 34-pin harness connector C242B terminal No. 14 (Gray/Black wire). If resistance is more than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, repair short to ground in Gray/Black wire between instrument cluster and CJB. See WIRING DIAGRAMS . Retest system operation.
- Turn ignition switch to ON position. Measure voltage between ground and CJB 34-pin harness connector C242B terminal No. 22 (Gray/Black wire). If battery voltage is not present, go to next step. If battery voltage is present, repair short to power in Gray/Black wire between instrument cluster and CJB. See WIRING DIAGRAMS . Retest system operation.
- Turn ignition switch to START position. Measure resistance between ground and instrument cluster 16-pin harness connector C250B terminal No. 10 (Gray/Black wire). If resistance is more than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, repair short to ground in Gray/Black wire between instrument cluster and CJB. See WIRING DIAGRAMS . Retest system operation.
- Turn ignition switch to LOCK position. Disconnect Anti-Lock Brake System (ABS) module 24-pin harness connector C104A. ABS module is located in left front of engine compartment, near air cleaner. Measure voltage between ground and ABS module 24-pin harness connector C104A terminal No. 16 (Gray/Black wire). See Fig 2. If battery voltage is not present, go to next step. If battery voltage is present, repair short to power in Gray/Black wire between instrument cluster and CJB. See WIRING DIAGRAMS . Retest system operation.
- Measure voltage between ground and instrument cluster 16-pin harness connector C250B terminal No. 8 (Red/White wire). See Figure. If battery voltage is present, go to next step. If battery voltage is not present, repair open in Red/White wire between instrument cluster and ECT sender. See WIRING DIAGRAMS . Retest system operation.
- Turn ignition switch to LOCK position. Check for corrosion, pushed out pins and harness connectors that are not connected correctly. Repair any damage found and reconnect any loose harness connectors. Retest system operation. If problem does not exist, system is operating correctly at this time. Clear any DTCs. If problem exists, replace instrument cluster. See REMOVAL & INSTALLATION . Retest system operation.
Courtesy of FORD MOTOR CO.
Courtesy of FORD MOTOR CO.