Left Lumbar Support Does Not Move Up Or Down

NOTE: This procedure applies to vehicles equipped with memory systems only.

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.
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). See WIRING DIAGRAMS . 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 .
Move left lumbar switch to inoperative position. If MSM beeps once when switch is moved to inoperative position, go to step 11 . If MSM does not beep once when switch is moved to inoperative position, go to next step.
Disconnect left lumbar switch connector. Move left lumbar switch to inoperative position. Using DVOM, measure resistance between Black wire terminal and appropriate left lumbar switch terminal (switch-side). See LEFT LUMBAR SWITCH CONNECTOR TERMINAL IDENTIFICATION table. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, go to step 6 .
Repair open in appropriate wire. After repairs, go to step 19 .
Replace left lumbar switch. See POWER SEATS - DEVILLE & ELDORADO article. After repairs, go to step 19 .
Check for poor connections at MSM. If poor connections are found, go to step 14 . If connections are okay, go to next step.
Check for open or short to ground in Orange wire between MSM connector C2 terminal "D" and splice S306 located in rear body harness approximately 2" from rear seat channel harness breakout. If faulty circuit is found, go to step 15 . If circuit is okay, go to next step.
Check for open in Black wire between MSM connector C2 terminal "C" and splice S351 located in left seat harness approximately 2" from power seat motor harness breakout. If faulty circuit is found, go to step 16 . If circuit is okay, go to next step.
Check for open in Red wire between MSM connector C2 terminal "B" and splice S311 located under left seat approximately 14" from ground harness breakout. If faulty circuit is found, go to step 17 . If circuit is okay, go to step 18 .
Disconnect suspect seat lumbar 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 13 .
Repair open or short to ground in appropriate wire between suspect motor and MSM. See WIRING DIAGRAMS . After repairs, go to step 19 .
Replace suspect seat lumbar motor. See POWER SEATS - DEVILLE & ELDORADO article. After repairs, go to step 19 .
Repair faulty terminals. After repairs, go to step 19 .
Repair open in Orange wire between MSM and splice S306. After repairs, go to step 19 .
Repair open in Black wire between MSM and splice S351. After repairs, go to step 19 .
Repair open in Red wire between MSM connector C2 terminal "B" and splice S311. After repairs, go to step 19 .
Replace MSM. See MEMORY SEAT MODULE under REMOVAL & INSTALLATION. After repairs, go to next step.
Perform LUMBAR SUPPORT MEMORY SYSTEM CHECK under TROUBLE SHOOTING.

LEFT LUMBAR SWITCH CONNECTOR TERMINAL IDENTIFICATION

Lumbar Direction

Terminal

Wire Color

DeVille

Down

"C"

Yellow

"D"

Red

In ⁽¹⁾

"A"

Gray

Out ⁽¹⁾

"B"

Purple

Eldorado