Circuit/System Testing

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF, disconnect the X1, X4 harness connectors at the MSM.
Test for infinite resistance between the control circuit terminal 14 X1 and ground.
- If not the specified value, test the control circuits listed below for a short to ground:
  - Driver seat cushion and back element terminal 14 X1
  - Driver seat cushion element terminal 11 X1
  - Driver seat back element terminal 1 X1
Test for infinite resistance between the control circuit terminal 6 X1 and ground.
- If not the specified value, test the control circuits listed below for a short to ground:
  - Passenger seat cushion and back element terminal 6 X1
  - Passenger seat cushion element terminal 14 X4
  - Passenger seat back element terminal 4 X1
Ignition ON, verify that a test lamp does not illuminate between the supply voltage circuit terminal 14 X1 and ground.
- If the test lamp illuminates, test the control circuits listed below for a short to voltage:
  - Driver seat cushion and back element terminal 14 X1
  - Driver seat cushion element terminal 11 X1
  - Driver seat back element terminal 1 X1
Verify that a test lamp does not illuminate between the supply voltage circuit terminal 6 X1 and ground.
- If the test lamp illuminates, test the control circuits listed below for a short to voltage:
  - Passenger seat cushion and back element terminal 6 X1
  - Passenger seat cushion element terminal 14 X4
  - Passenger seat back element terminal 4 X1
If all circuits test normal, replace the MSM.