Lumbar Switch Circuit Test
WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the harness connector at the lumbar adjuster switch.
- 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.
- Verify that all scan tool lumbar switch parameters are Inactive.
- If not the specified value, test the appropriate signal circuits listed below for a short to voltage. If the circuit tests normal, replace the MSM.
- 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 appropriate signal circuits listed below for a short to voltage. If the circuit tests normal, replace the MSM.
- 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.
- If all circuits test normal, test or replace the lumbar switch.