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Home >> Chevrolet >> 2012 >> Traverse LS, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 172 (Mirror System) >> Diagnostic Information and Procedures >> DTC B1640 >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2013 GMC Acadia, 2013 Chevrolet Traverse, and 2013 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector X1 (RPO W49) or X2 (RPO DNP) at the outside rearview mirror.
  2. Wait 1 minute, test for less than 1.0 ohm between the ground circuit terminal 3 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the appropriate door switch.
  3. Connect a test lamp between the control circuit terminal 7 and ground.
  4. Ignition ON, command the mirror heater ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    • If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the door switch.
    • If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the door switch.
  5. If all circuits test normal, test or replace the outside rearview mirror glass.
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