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Circuit/System Testing

WARNING: This page is about a different car, the 2016 GMC Acadia, 2016 Chevrolet Traverse, and 2016 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect all of the KR20 Cooling Fan Relays.
  2. Ignition ON, verify a test lamp illuminates between ground and the B+ circuit terminals listed below:
    • KR20J Cooling Fan Low Speed Relay B+ circuit terminal 85/1
    • KR20J Cooling Fan Low Speed Relay B+ circuit terminal 30/3
    • KR20K Cooling Fan High Speed Relay B+ circuit terminal 30/3
    • KR20K Cooling Fan High Speed Relay B+ circuit terminal 85/1.
    • KR20E Cooling Fan Speed Control Relay B+ circuit terminal 86/2
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Disconnect the appropriate cooling fan fuse or power source.
    2. Test for less than 2 Ω between the fuse and the appropriate relay B+ circuit terminal, end to end.
      • If 2 Ω or greater, repair the open/high resistance in the B+ 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. Connect a DMM to the appropriate relay B+ circuit terminal.
    2. Test for infinite resistance between the B+ circuit and ground.
      • If less than infinite resistance, repair the short to ground on the B+ circuit.
      • If infinite resistance
    3. Disconnect the harness connector at the appropriate G10 Cooling Fan Motor.
    4. Test for infinite resistance between the appropriate relay controlled output circuit terminal and ground.
      • KR20J Cooling Fan Low Speed Relay output circuit terminal 87/5
      • KR20K Cooling Fan High Speed Relay output circuit terminal 87/5
      • KR20E Cooling Fan Speed Control Relay circuit terminal 30/3
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, test or replace the appropriate G10 Cooling Fan Motor.
    • If the test lamp illuminates 
    3. NOTE:

    The following tests must be performed on both fan relay circuits.

  3. Connect a DMM, set on the diode setting, between ground and a relay control circuit terminal listed below:
    • KR20K Cooling Fan High Speed Relay terminal 86/1
    • KR20E Cooling Fan Speed Control Relay terminal 85/2
  4. Verify the DMM reading is less than 1 V when commanding the cooling fan relays ON with a scan tool.
    • If greater than 1 V or displays OL. 
    1. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module, ignition ON.
    2. Test for less than 1 V between the appropriate cooling fan relay control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V.
    3. Ignition OFF, and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.
    4. Test for less than 2 Ω between the KR20E Cooling Fan Speed Control Relay terminal 85/2 and KR20K Cooling Fan High Speed Relay terminal 86/1.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K20 Engine Control Module.
    • If less than 1 V 
  5. Ignition OFF and all vehicle systems OFF, disconnect the harness connector X104. It may take up to 2 minutes for all vehicle systems to power down.
  6. Test for less than 5 Ω between the circuits listed below and ground:
    • KR20E Cooling Fan Speed Control Relay terminal 87A/4
    • KR20E Cooling Fan Speed Control Relay terminal 87/5
    • If 5 Ω or greater 
    1. Ignition OFF and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down.
    2. Test for less than 2 Ω in the appropriate ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • If less than 5 Ω 
  7. Ignition OFF and all vehicle systems OFF, disconnect the harness connector X104. It may take up to 2 minutes for all vehicle systems to power down.
  8. Test for less than 2 Ω in the circuit between connector X104 terminal D and the KR20E Cooling Fan Speed Control Relay terminal 30/3.
    • If 2 Ω or greater, repair the open/high resistance in the circuit.
    • If less than 2 Ω 
  9. Connect the harness connector X104.
  10. Connect a 50 A fused jumper between the KR20K Cooling Fan High Speed Relay terminals 30/3 and 87/5.
  11. Ignition ON, verify the G10R Cooling Fan Motor-Right is activated at high speed.
    • If the cooling fan does not activate or jumper fuse opens 
    1. Disconnect the harness connector X104.
    2. Test for less than 2 Ω in the circuit between KR20K Cooling Fan High Speed Relay terminal 87/5 and Connector X104 terminal D.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the G10L Cooling Fan Motor-Left.
    • If the cooling fan activates 
  12. Ignition OFF, connect a fused jumper between the KR20E Cooling Fan Speed Control Relay switch circuit terminal 30/3 and the ground circuit terminal 87/5.
  13. Connect a 40 A fused jumper between the KR20J Cooling Fan Low Speed Relay terminals 30/3 and 87/5.
  14. Ignition ON, verify the G10L Cooling Fan Motor-Left is activated at high speed.
    • If the cooling fan does not activate 
    1. Disconnect the harness connector X104.
    2. Test for less than 2 Ω in the circuit between KR20E Cooling Fan Low Speed Relay terminal 87A/5 and connector X104 terminal B.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω
      • If less than 2 Ω, replace the G10R Cooling Fan Motor-Right.
    • If the cooling fan activates 
  15. Ignition OFF, Install the KR20E Cooling Fan Speed Control Relay.
  16. Ignition ON, verify both fan motors activate at low speed.
    • If both cooling fans do not activate at low speed 
    1. Test for infinite resistance between KR20E Cooling Fan Speed Control Relay terminal listed below and ground.
      • KR20E Cooling Fan Speed Control Relay terminal 30/3
      • KR20E Cooling Fan Speed Control Relay terminal 87A/4
      • If less than infinite, repair the short to ground in the circuit.
      • If infinite, replace the KR20E cooling fan speed control relay.
    • If both cooling fans activate 
  17. Ignition OFF, test or replace the cooling fan relay listed below as appropriate:
    • KR20J Cooling Fan Low Speed Relay
    • KR20K Cooling Fan High Speed Relay
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