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Home >> Cadillac >> 2017 >> CT6 Plug-In >> Repair and Diagnosis (Single Page) >> Hybrid/Electric Powertrain >> Cooling Systems >> Hybrid/EV System Heating And Cooling >> Diagnostic Information and Procedures >> DTC P0480: Cooling Fan Relay 1 Control Circuit >> Circuit/System Testing
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Circuit/System Testing

  1. Vehicle OFF, disconnect the harness connector at the G10 Cooling Fan Motor.
  2. Test for less than 10 Ω between the ground circuit terminal 2 and ground.
    • If 10 Ω or greater 

      Repair the open/high resistance in the circuit.

    • If less than 10 Ω 
  3. Connect a test lamp between the B+ circuit terminal 1 and ground.
  4. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Vehicle OFF.
    2. Test for less than 2 Ω in the B+ circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Vehicle OFF.
    2. Test for infinite resistance between the B+ circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the G10 Cooling Fan Motor and the fuse.
    • If the test lamp illuminates 
  5. Connect a test lamp between the control circuit terminal 4 and the B+ circuit terminal 1.
  6. Verify the test lamp changes between dim (20%) and bright (90%) when commanding the Cooling Fan Motor Command ON between 20% and 90% with a scan tool.
    • If the test lamp is always dim or does not illuminate 
    1. Vehicle OFF, disconnect the X2 harness connector at the K114B Hybrid/EV Powertrain Control Module 2. Vehicle in Service Mode.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V
    3. Vehicle OFF.
    4. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K114B Hybrid/EV Powertrain Control Module 2.
    • If the test lamp is always bright 
    1. Vehicle OFF, disconnect the X2 harness connector at the K114B Hybrid/EV Powertrain Control Module 2.
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K114B Hybrid/EV Powertrain Control Module 2.
    • If the test lamp changes illumination between bright (90%) and dim (20%) 
  7. Replace the G10 cooling fan motor.
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