Circuit/System Testing

2006 Chevrolet Chevy Express G2500, Van Cargo, 6.6 2SECTION Circuit/System Testing
WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.

Mirror Position Sensor Circuit Malfunction

  1. Ignition OFF, disconnect the inline harness connector at the outside rearview mirror.
  2. Ignition OFF, test for less than 1.0 ohm between the low reference circuit terminal 12 and ground.
    • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the appropriate door module.
  3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 9 and ground.
    • If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the appropriate door module.
    • If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the appropriate door module.
  4. Install a 3A fused jumper wire between the signal circuit terminal 10 and the low reference circuit terminal 12. Verify the scan tool Mirror Vertical Position parameter is less than 0.2 volts.
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the appropriate door module.
  5. Install a 3A fused jumper wire between the signal circuit terminal 11 and the low reference circuit terminal 12. Verify the scan tool Mirror Horizontal Position parameter is less than 0.2 volts.
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the appropriate door module.
  6. Install a 3A fused jumper wire between the signal circuit terminal 10 and the 5-volt reference circuit terminal 9. Verify the scan tool Mirror Vertical Position parameter is greater than 4.8 volts
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the appropriate door module.
  7. Install a 3A fused jumper wire between the signal circuit terminal 11 and the 5-volt reference circuit terminal 9. Verify the scan tool Mirror Horizontal Position parameter is greater than 4.8 volts.
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the appropriate door module.
  8. If all circuits test normal, test or replace the appropriate outside rearview mirror motor.

Mirror Motor Circuit Malfunction

  1. Ignition OFF, disconnect the inline harness connector at the outside rearview mirror.
  2. Install a test lamp between the control circuit terminal 3 and the control circuit terminal 2.
  3. Ignition ON, commanded the mirror left and right using the mirror directional switch. The test lamp should turn ON and OFF as the mirror commanded to the left and right.
    • If the test lamp does not turn ON and OFF when cycling between the commanded states, test both control circuit for a short to voltage, a short to ground, or an open/high resistance. If the circuits test normal, replace the applicable door module.
  4. Ignition OFF, install a test lamp between the control circuit terminal 1 and the control circuit terminal 2.
  5. Ignition ON, commanded the mirror up and down using the mirror directional switch. The test lamp should turn ON and OFF as the mirror commanded up and down.
    • If the test lamp does not turn ON and OFF when cycling between the commanded states, test both control circuit for a short to voltage, a short to ground, or an open/high resistance. If the circuits test normal, replace the applicable door module.
  6. If all circuits test normal, test or replace the outside rearview mirror motor.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

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