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Left Lumbar Support Inoperative

NOTE: This procedure applies to vehicles equipped with memory systems only.
  1. If lumbar support memory system check was performed, go to next step. If lumbar support memory system check was not performed, go to LUMBAR SUPPORT MEMORY SYSTEM CHECK  under TROUBLE SHOOTING.
  2. Disconnect Memory Seat Module (MSM) Light Green, 6-pin connector C2. See Fig 1 . Using DVOM, measure voltage between MSM harness connector C2, terminals "D" (Orange wire) and "C" (Black wire). See WIRING DIAGRAMS  . If battery voltage is indicated, go to next step. If battery voltage is not indicated, go to step  5 .
  3. Disconnect left lumbar switch connector. Measure voltage between MSM harness connector C2, terminal "D" (Orange wire) and left lumbar switch harness connector terminal "E" (Black wire). If battery voltage is indicated, go to next step. If battery voltage is not indicated, go to step  6 .
  4. Replace left lumbar switch. See POWER SEATS - DEVILLE & ELDORADO article.
  5. Repair open in Black wire between MSM and splice S351 located in left seat harness approximately 2" from power seat motor harness breakout. After repairs, go to LUMBAR SUPPORT MEMORY SYSTEM CHECK  under TROUBLE SHOOTING.
  6. Repair open in Black wire between left lumbar switch and splice S351 located in left seat harness approximately 2" from power seat motor harness breakout. After repairs, go to LUMBAR SUPPORT MEMORY SYSTEM CHECK  under TROUBLE SHOOTING.
Fig 1: Identifying Memory Seat Module (MSM) Connector C2 (Light Green), C3 (Black) & C4 (Natural).
G98B01726Courtesy of GENERAL MOTORS CORP.
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