Circuit/System Testing

Compass Display Is Incorrect

1. Adjust or change the compass zone using the world magnetic variation map. Refer to Compass Calibration and Magnetic Variance (without OnStar Only) .
   • If the compass is still incorrect, perform the compass magnetic variation adjustment procedure. Refer to Compass Calibration and Magnetic Variance (without OnStar Only) .
2. If the compass is still incorrect, replace the compass module.

Compass Displays CAL

1. Perform the compass magnetic variation adjustment procedure. Refer to Compass Calibration and Magnetic Variance (without OnStar Only) .
2. If the compass still displays CAL, replace the compass module.

Compass Displays No Heading

1. Ignition OFF, disconnect the harness connector at the compass module.
2. Test for less than 5 Ω between the low reference circuit terminal 2 and ground.
   • If greater than the specified range, test the circuit for a short to voltage or an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between the voltage circuit terminal 1 and ground.
   • If the test lamp does not illuminate, repair the circuit for a short to ground or an open/high resistance.
4. Ignition OFF, test for greater than 1 Ω between the compass LIN 3 data circuit terminal 3 and ground.
   • If less than the specified range, test the LIN 3 data circuit for a short to ground.
5. Ignition ON, verify that a test lamp does not illuminate between the compass LIN 3 data circuit terminal 3 and ground
   • If the test lamp illuminates, test the LIN 3 data circuit for a short to voltage.
6. Ignition OFF, disconnect the X4 harness connector at the BCM.
7. Test for less than 1 Ω between the compass LIN 3 data circuit terminal 3 to the BCM terminal 6.
   • If greater than the specified range, repair the LIN 3 data circuit for an open/high resistance.
8. If all circuits test normal, replace the compass module.