LEMON Manuals: Even more car manuals for everyone
Home >> Cadillac >> 2021 >> CT4 Sport, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 50 (Mirrors) >> Diagnostic Information and Procedures >> Automatic Day-Night Mirrors Malfunction >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

Inside Review Mirror Dimming Inoperative

  1. Ignition OFF and all vehicle systems OFF, disconnect the connector at the A10 Inside Rearview Mirror. It may take up to 2 minutes for all vehicle systems to power down.
  2. Verify a test lamp illuminates between ground circuit terminal 5 and B+.
    • If the test lamp does not illuminate 
    1. Repair the open/high resistance on the ground circuit or ground connection.
    • Go to next step: If the test lamp illuminates 
  3. Ignition ON.
  4. Verify a test lamp illuminates between the ignition circuit terminal 2 and ground.
    • If the test lamp does not illuminate 
    1. Test circuit 1839 for a short to ground.
      • If a short to ground is found, repair the fault on the circuit.
      • Go to next step: If a short to ground is not found.
    2. Test circuit 1839 for an open/high resistance.
      • If an open/high resistance is found, repair the fault on the circuit.
      • Go to next step: If an open/high resistance is not found.
    3. Replace X51A Fuse Block - Instrument Panel for an internal fault.
    • Go to next step: If the test lamp illuminates 
  5. Replace the A10 Inside Rearview Mirror.

Day-Night Disable Malfunction

  1. Ignition OFF, disconnect the connector at the A10 Inside Rearview Mirror.
  2. Connect a test lamp between the control circuit terminal 1 and ground
  3. Ignition ON, verify the test lamp turns ON and OFF while commanding the Backup Lamps Active and Inactive with a scan tool.
    • If the test lamp is always OFF 
    1. Test circuit 24 for a short to ground.
      • If a short to ground is found, repair the fault on the circuit.
      • Go to next step: If a short to ground is not found.
    2. Test circuit 24 for an open/high resistance.
      • If an open/high resistance is found, repair the fault on the circuit.
    • If the test lamp is always ON 
    1. Test circuit 24 for a short to voltage.
      • If a short to voltage is found, repair the fault on the circuit.
    • Go to next step: If the test lamp turns ON and OFF 
  4. Replace the A10 Inside Rearview Mirror.

Outside Rearview Mirror Dimming Malfunction

  1. Ignition OFF and all vehicle systems OFF, disconnect the X510 inline connector at the A9A Outside Rearview Mirror-Driver. It may take up to 2 minutes for all vehicle systems to power down.
  2. Verify a test lamp illuminates between the low reference circuit terminal 12 and ground.
    • If the test lamp does not illuminate 
    1. Test circuit 1691 for an open/high resistance.
      • If an open/high resistance is found, repair the fault on the circuit.
      • Go to next step: If an open/high resistance is not found.
    2. Replace A10 Inside Rearview Mirror for an internal fault.
    • Go to next step: If the test lamp illuminates 
  3. Ignition ON.
  4. Test for less than 1 V between the control circuit terminal 17 and ground.
    • If 1 V or greater 
    1. Test circuit 1690 for a short to voltage.
      • If a short to voltage is found, repair the fault on the circuit.
      • Go to next step: If a short to voltage is not found.
    2. Replace the A10 Inside Rearview Mirror.
    • Go to next step: If less than 1 V 
  5. Ignition ON, headlamps ON, vehicle in PARK, cover the front light sensor with a towel or other suitable item. Shine a flashlight at the rear light sensor.
  6. Test for greater than 1 V between the control circuit terminal 2 and ground.
    • If 1 V or less 
    1. Test circuit 1690 for a short to ground.
      • If a short to ground is found, repair the fault on the circuit.
      • Go to next step: If a short to ground is not found.
    2. Test circuit 1690 for an open/high resistance.
      • If an open/high resistance is found, repair the fault on the circuit.
      • Go to next step: If an open/high resistance is not found.
    3. Replace A10 Inside Rearview Mirror for an internal fault.
    • Go to next step: If greater than 1 V 
  7. Replace E17D Outside Rearview Mirror Glass-Driver.
scientia non olet · About LEMON Manuals