LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Cadillac >> 2000 >> Seville STS >> Repair and Diagnosis >> Steering >> Steering Column >> Memory Systems >> Symptom Tests >> Test 20: Lumbar Support Does Not Move Up/Down - With A45
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Test 20: Lumbar Support Does Not Move Up/Down - With A45

  1. Perform POWER SEAT DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM in POWER SEATS - SEVILLE article. Go to next step.
  2. Install a scan tool. Turn ignition switch to ON position, engine off. Using scan tool, observe SEAT LUMBAR UP parameter in MEMORY SEAT MODULE data list. Operate lumbar switch in up direction. If SEAT LUMBAR UP parameter changes state, go to next step. If SEAT LUMBAR UP parameter does not change state, go to step  5 .
  3. Using scan tool, observe SEAT LUMBAR DOWN parameter. Operate lumbar switch in down direction. If SEAT LUMBAR DOWN parameter changes state, go to next step. If SEAT LUMBAR DOWN parameter does not change state, go to step  6 .
  4. Disconnect seat lumbar horizontal motor connector. Connect a test light between 2-pin lumbar horizontal motor connector terminals "A" (Tan wire) and "B" (Purple wire). Operate lumbar switch in up and down directions. If test light illuminates in both directions, go to step  13 . If test light does not illuminate in both directions, go to step  7 .
  5. Disconnect lumbar switch connector. Using scan tool, observe SEAT LUMBAR UP parameter. Connect fused jumper wire (3-amp) between battery voltage and lumbar switch connector terminal "B" (White wire). See Figure . If SEAT LUMBAR UP parameter changes state, go to step  12 . If SEAT LUMBAR UP parameter does not change state, go to step  9 .
  6. Disconnect lumbar switch connector. Using scan tool, observe SEAT LUMBAR DOWN parameter. Connect fused jumper wire (3-amp) between battery voltage and lumbar switch connector terminal "C" (Yellow/Black wire). See Figure . If SEAT LUMBAR DOWN parameter changes state, go to step  12 . If SEAT LUMBAR DOWN parameter does not change state, go to step  10 .
  7. Check Tan wire between Memory Seat Module (MSM) and lumbar horizontal motor for short to ground or open. If problem is found, repair as necessary, then go to step  17 . If problem is not found, go to next step.
  8. Check Purple wire between MSM and lumbar horizontal motor for short to ground or open. If problem is found, repair as necessary, then go to step  17 . If problem is not found, go to step  11 .
  9. Check White wire between lumbar switch and Memory Seat Module (MSM) for open. If problem is found, repair as necessary, then go to step  17 . If problem is not found, go to step  11 .
  10. Check Yellow/Black wire between lumbar switch and Memory Seat Module (MSM) for open. If problem is found, repair as necessary, then go to step  17 . If problem is not found, go to next step.
  11. Check MSM connector for poor connections. If problem is found, repair as necessary, then go to step  17 . If problem is not found, go to step  14 .
  12. Check lumbar switch connector for poor connections. If problem is found, repair as necessary, then go to step  17 . If problem is not found, go to step  15 .
  13. Check lumbar vertical motor connector for poor connections. If problem is found, repair as necessary, then go to step  17 . If problem is not found, go to step  16 .
  14. Replace MSM. See MEMORY SEAT MODULE  under REMOVAL & INSTALLATION. After repairs, go to step  17 .
  15. Replace lumbar switch. See POWER SEAT SWITCHES under REMOVAL & INSTALLATION in POWER SEATS - SEVILLE article. After repairs, go to step  17 .
  16. Replace lumbar vertical motor. See SEAT MOTORS under REMOVAL & INSTALLATION in POWER SEATS - SEVILLE article. After repairs, go to next step.
  17. Operate system to verify repair. If system operates normally, repair is complete. If system does not operate normally, return to step  2 .
scientia non olet · About LEMON Manuals