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Lumbar Support Does Not Move Up Or Down (With Am3)

NOTE: This procedure applies to vehicles equipped with memory systems (A45) and massaging lumbar (AM3). For option code definition, see REGULAR PRODUCTION OPTION CODES  under DESCRIPTION.
  1. If power seats diagnostic system check was performed, go to next step. If power seats diagnostic system check was not performed, go to POWER SEATS DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC TESTS.
  2. Connect scan tool to Data Link Connector (DLC). See Figure . Turn ignition on. Using scan tool, select MEMORY SEAT MODULE data list. Monitor SEAT LUMBAR UP status. Operate the lumbar switch in up position. If SEAT LUMBAR UP status changes, go to next step. If SEAT LUMBAR UP status does not change, go to step  4 .
  3. Monitor SEAT LUMBAR DOWN status. Operate the lumbar switch in up position. If SEAT LUMBAR DOWN status does not change, go to step  5 . If SEAT LUMBAR DOWN status changes, go to step  8 .
  4. Turn ignition off. Disconnect lumbar massage module connector. See Figure . Connect a test light between ground and lumbar massage module connector terminal "G" (Light Blue wire). See Figure . Operate driver's lumbar switch in up position. If test light illuminates, go to step  6 . If test light does not illuminate, go to step  11 .
  5. Turn ignition off. Disconnect lumbar massage module connector. See Figure . Connect a test light between ground and lumbar massage module connector terminal "H" (Brown wire). See Figure . Operate driver's lumbar switch in down position. If test light illuminates, go to step  7 . If test light does not illuminate, go to step  11 .
  6. Turn ignition on. Connect a 3-amp fused jumper wire between battery positive voltage (B+) and lumbar massage module connector terminal "S" (Dark Blue wire). Monitor SEAT LUMBAR UP status. If SEAT LUMBAR UP status does not change, go to step  12 . If SEAT LUMBAR UP status changes, go to step  17 .
  7. Turn ignition on. Connect a 3-amp fused jumper wire between battery positive voltage (B+) and lumbar massage module connector terminal "R" (Light Blue wire). Monitor SEAT LUMBAR DOWN status. If SEAT LUMBAR DOWN status does not change, go to step  12 . If SEAT LUMBAR DOWN status changes, go to step  17 .
  8. Disconnect lumbar vertical motor connector. See Figure . Connect a test light between lumbar vertical motor connector terminals "A" (Purple wire) and "B" (Tan wire). Operate driver's lumbar switch to up and down positions. If test light does not illuminate in both directions, go to next step. If test light illuminates in both directions, go to step  16 .
  9. Disconnect Memory Seat Module (MSM) connector. See Figure . Connect a test light between ground and lumbar massage module connector terminal "S" (Dark Blue wire). Connect a 3-amp fused jumper wire between battery positive voltage (B+) and MSM connector C2 terminal E11 (Dark Blue wire). If test light illuminates, go to next step. If test light does not illuminate, go to step  13 .
  10. Disconnect Memory Seat Module (MSM) connector. See Figure . Connect a test light between ground and lumbar massage module connector terminal "R" (Light Blue wire). Connect a 3-amp fused jumper wire between battery positive voltage (B+) and MSM connector C2 terminal E12 (Dark Light Blue wire). If test light illuminates, go to step  14 . If test light does not illuminate, go to step  13 .
  11. Check for open or high resistance in Brown wire between lumbar switch connector terminal "C" and lumbar massage module connector terminal "H". See Figure . Check for open or high resistance in Light Blue wire between lumbar switch connector terminal "B" and lumbar massage module connector terminal "G". If circuits are okay, go to step  15 . If faulty circuit is found and repaired, go to step  23 .
  12. Check for open, high resistance or short to ground in Light Blue wire between MSM connector C2 terminal E12 and lumbar massage module connector terminal "R". Check for open, high resistance or short to ground in Dark Blue wire between MSM connector C2 terminal E11 and lumbar massage module connector terminal "S". If circuits are okay, go to step  18 . If faulty circuit is found and repaired, go to step  23 .
  13. Check for open, high resistance or short to ground in Light Blue wire between MSM connector C2 terminal E12 and lumbar massage module connector terminal "R". Check for open, high resistance or short to ground in Dark Blue wire between MSM connector C2 terminal E11 and lumbar massage module connector terminal "S". If circuits are okay, go to step  18 . If faulty circuit is found and repaired, go to step  23 .
  14. Check for open or short to ground in Tan wire between lumbar vertical motor connector terminal "A" and lumbar massage module connector terminal "B". Check for open or short to ground in Purple wire between lumbar vertical motor connector terminal "B" and lumbar massage module connector terminal "C". If circuits are okay, go to step  17 . If faulty circuit is found and repaired, go to step  23 .
  15. Check for poor connections at driver's lumbar switch connector. If connections are okay, go to step  19 . If faulty connections are found and repaired, go to step  23 .
  16. Check for poor connections at lumbar vertical motor connector. If connections are okay, go to step  20 . If faulty connections are found and repaired, go to step  23 .
  17. Check for poor connections at lumbar massage module connector. See Figure . If connections are okay, go to step  21 . If faulty connections are found and repaired, go to step  23 .
  18. Check for poor connections at MSM connector. If connections are okay, go to step  22 . If faulty connections are found and repaired, go to step  23 .
  19. Replace driver's lumbar switch. See DRIVER'S POWER SEAT SWITCH  under REMOVAL & INSTALLATION. After repairs, go to step  23 .
  20. Replace seat lumbar vertical motor. See SEAT MOTORS under REMOVAL & INSTALLATION in POWER SEATS - DEVILLE article. After repairs, go to step  23 .
  21. Replace lumbar massage module. See LUMBAR MASSAGE MODULE  under REMOVAL & INSTALLATION. After repairs, go to step  23 .
  22. Replace MSM. See MEMORY SEAT MODULE  under REMOVAL & INSTALLATION. After repairs, go to next step.
  23. Recheck power lumbar operation. If power lumbar malfunction is still present, go to step  2 . If power lumbar malfunction is no longer present, repair is complete.
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