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Test B: No Communication With LCM

  1. Check For PID Data Access  - Turn ignition switch to RUN position. Using NGS tester, monitor LCM PID IGN_LC. If NGS tester does not indicate unable to perform test function, LCM not responding, check ignition status/verify cable requirements, or check cable connections, go to next step. If NGS tester indicates unable to perform test function, LCM not responding, check ignition status/verify cable requirements, or check cable connections, go to step 11).
  2. Verify LCM PID IGN_LC Input  - Turn ignition switch to RUN position. Using NGS tester, monitor LCM PID IGN_LC while rotating ignition switch through ACCY, OFF and RUN positions. If NGS tester indicates RUN while in RUN position, replace lighting control module and retest system operation. If NGS tester indicates START while in RUN position, go to next step. If NGS tester indicates ACCY while in RUN position, go to step 7).
  3. Check Fuse  - Turn ignition off. Check condition of instrument panel fuse No. 6 (15-amp). Remove instrument panel fuse block fuse No. 6. If fuse is okay, go to next step. If fuse is not okay, go to step 6).
  4. Check Power To Fuse No. 6 (15-Amp)  - Turn ignition switch to RUN position. Using a voltmeter, check voltage between ground and input cavity of instrument panel fuse box fuse No. 6 (15-amp). If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Black/Light Green wire to instrument panel fuse box and retest system operation.
  5. Check White/Purple Wire For Voltage  - Turn ignition off. Install fuse No. 6 (15-amp). Disconnect LCM 16-pin connector C2027 (located behind left side of instrument panel). Turn ignition switch to RUN position. Using a voltmeter, check voltage between ground and LCM 16-pin connector C2027 terminal No. 1 (White/Purple wire). See Fig 1 . If voltage is more than 10 volts, replace LCM and retest system operation. If voltage is 10 volts or less, repair open in White/Purple wire and retest system operation.
  6. Check White/Purple Wire For Short To Ground  - Turn ignition off. Using an ohmmeter, check resistance between ground and LCM 16-pin connector C2027 terminal No. 1 (White/Purple wire). See Fig 1 . If resistance is more than 10 k/ohms, replace LCM and retest system operation. If resistance is 10 k/ohms or less, repair short to ground in White/Purple wire and retest system operation.
  7. Check Fuse  - Turn ignition off. Check condition of instrument panel fuse No. 13 (15-amp). Remove instrument panel fuse block fuse No. 13. If fuse is okay, go to next step. If fuse is not okay, go to step 10).
  8. Check Power To Fuse No. 13 (15-Amp)  - Turn ignition switch to RUN position. Using a voltmeter, check voltage between ground and input cavity of instrument panel fuse box fuse No. 13 (15-amp). If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Brown/Pink wire to instrument panel fuse box and retest system operation.
  9. Check Red/Yellow Wire For Voltage  - Turn ignition off. Install fuse No. 13 (15-amp). Disconnect LCM 16-pin connector C2027 (located behind left side of instrument panel). Turn ignition switch to RUN position. Using a voltmeter, check voltage between ground and LCM 16-pin connector C2027 terminal No. 9 (Red/Yellow wire). See Fig 1 . If voltage is more than 10 volts, replace LCM and retest system operation. If voltage is 10 volts or less, repair open in Red/Yellow wire and retest system operation.
  10. Check Red/Yellow Wire For Short To Ground  - Turn ignition off. Using an ohmmeter, check resistance between ground and LCM 16-pin connector C2027 terminal No. 9 (Red/Yellow wire). See Fig 1 . If resistance is more than 10 k/ohms, replace LCM and retest system operation. If resistance is 10 k/ohms or less, repair short to ground in Red/Yellow wire and retest system operation.
  11. Check Black Wires For Open  - Turn ignition off. Disconnect LCM 16-pin connector C2029 (located behind left side of instrument panel). Using an ohmmeter, check resistance between ground and LCM 16-pin connector C2029 terminals No. 4 and 9. See Fig 2 . If resistances are 5 ohms or more, repair open in appropriate Black wire(s) and retest system operation. If resistances are less than 5 ohms, go to MODULE COMMUNICATIONS NETWORK article to diagnose network concern.
Fig 1: Identifying LCM Connector C2027 Terminals
G97F28386Courtesy of FORD MOTOR CO.
Fig 2: Identifying LCM Connector C2029 Terminals
G97H28388Courtesy of FORD MOTOR CO.
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