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Lumbar Support Inoperative

NOTE: This procedure applies to vehicles equipped with memory systems (A45). 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. Using DVOM connected to ground, backprobe and measure voltage at driver's lumbar switch connector terminal "G" (Orange wire). See Fig 1 . If voltage is 9-16 volts, go to next step. If voltage is not 9-16 volts, go to step  6 .
  3. If lumbar moves when memory recall function is performed, go to next step. If lumbar does not move when memory recall function is performed, go to step  5 .
  4. Check for poor connections at driver's lumbar switch connector. If connections are okay, go to step  7 . If faulty connections are found and repaired, go to step  9 .
  5. Check for poor connections at Memory Seat Module (MSM) connector. See Figure . If connections are okay, go to step  8 . If faulty connections are found and repaired, go to step  9 .
  6. Repair open in Orange wire between lumbar switch and rear fuse block located under rear seat cushion. See Figure . After repairs, go to step  9 .
  7. Replace driver's lumbar switch. See DRIVER'S POWER SEAT SWITCH  under REMOVAL & INSTALLATION. After repairs, go to step  9 .
  8. Replace MSM. See MEMORY SEAT MODULE  under REMOVAL & INSTALLATION. After repairs, go to next step.
  9. 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.
Fig 1: Identifying Lumbar Switch Connector Terminals (A45 With AC9, AL2 or AM3)
G00016912Courtesy of GENERAL MOTORS CORP.