Circuit/System Testing

Lumbar Switch Circuit Test

1. Ignition OFF, disconnect the harness connector at the lumbar switch.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal G and ground.
   • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the MSM.
3. Install a 3A fused jumper wire between the appropriate signal circuit listed below and the B+ circuit terminal G. Verify the scan tool Lumbar Switch parameter is Active.
   • Lumbar horizontal forward terminal C
   • Lumbar horizontal rearward terminal B
   • Lumbar vertical upward terminal F
   • Lumbar vertical downward terminal A
   • If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the MSM.
4. If all circuits test normal, test or replace the lumbar switch.

Lumbar Motor Control Circuit Test

1. Ignition OFF, disconnect the harness connector at the appropriate lumbar motor.
2. Connect a test lamp between the control circuit terminal A and control circuit terminal B.
3. Ignition ON, command the appropriate lumbar motor in the Up/Down or Froward/Rearward directions with a scan tool. The test lamp should turn ON when commanding the up and down or froward and rearward states.
   • If the test lamp remains OFF during either of the commands, test the control circuits for a short to ground or an open/high resistance. If the circuits test normal replace the MSM.
4. If all circuits test normal, test or replace the lumbar motor.