1998 Cadillac Eldorado BaseFACTORY OEM SERVICE PROCEDURE

Left Lumbar Support Does Not Manually Move In One Direction

NOTE: After repair or component replacement is completed, perform MEMORY SYSTEM CHECK  under TESING - SYSTEM CHECKS to verify system is operating properly.
  1. Perform MEMORY SYSTEM CHECK  under TESTING - SYSTEM CHECKS. Go to next step.
  2. Turn ignition off. Enter Mode 1 Diagnostics by grounding Memory Seat Module (MSM) diagnostic connector, located under left seat (connector must remain grounded throughout test). MSM should beep once to confirm that Mode 1 Diagnostics has been entered. While in Mode 1 Diagnostics, all seat and recliner movements are disabled. If one beep was heard, go to next step. If one beep was not heard, go to step 7).
  3. Move left lumbar switch to inoperative position. If MSM beeps once when switch is moved to inoperative position, go to step 8). If MSM does not beep once when switch is moved to inoperative position, go to next step.
  4. Disconnect left lumbar switch connector. Move left lumbar switch to inoperative position. Using DVOM, check resistance between Black wire terminal and appropriate left lumbar switch terminal (switch-side). See WIRING DIAGRAMS  . If resistance is less than 5 ohms, go to next step. If resistance is not less than 5 ohms, go to step 6).
  5. Repair open in appropriate wire. See WIRING DIAGRAMS  .
  6. Replace left lumbar switch. See SEATS - POWER article.
  7. Check power and ground circuits to MSM. See WIRING DIAGRAMS  . Check for poor connections at MSM. If circuits and connections are okay, replace MSM.
  8. Disconnect suspect seat motor. Connect a fused jumper (20-amp) wire between one motor terminal and battery voltage. Connect another fused jumper (20-amp) wire between other motor terminal and ground. If motor runs, go to next step. If motor does not run, go to step 10).
  9. Repair open or short to ground in appropriate wire between suspect motor and MSM. See WIRING DIAGRAMS  .
  10. Replace suspect seat motor. See SEATS - POWER article.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.