1998 Cadillac DeVille BaseFACTORY OEM SERVICE PROCEDURE

Left Seat Does Not Manually Move In Any Direction

NOTE: After repair or component replacement is completed, perform MEMORY SYSTEM CHECK  under TESTING - SYSTEM CHECKS to verify system is operating properly.
  1. Perform MEMORY SYSTEM CHECK  under TESTING - SYSTEM CHECKS. Go to next step.
  2. Disconnect Memory Seat Module (MSM) Light Green, 6-pin connector C2. Using DVOM, check voltage between MSM harness connector C2, terminals "D" (Orange wire) and "C" (Black wire). If 10-15 volts exists, go to next step. If 10-15 volts does not exist, go to step 5).
  3. Disconnect left seat switch Black, 10-pin connector. Using DVOM, measure voltage between left seat switch connector terminal "J" (Black wire) and ground. If 10-15 volts exists, go to next step. If 10-15 volts does not exist, go to step 6).
  4. Replace left seat switch. See SEATS - POWER article. Perform MEMORY SYSTEM CHECK  .
  5. Repair open in circuit No. 850 (Black wire) between MSM and splice S351. See WIRING DIAGRAMS  . Perform MEMORY SYSTEM CHECK  .
  6. Repair open in circuit No. 50 (Black wire) between left seat switch and splice S200. See WIRING DIAGRAMS  .
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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.