LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2015 >> Cruze LT, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 57 (Engine Cooling System) >> Diagnostic Information and Procedures >> Cooling Fan Inoperative (LUV) >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2015 Chevrolet Trax and 2015 Buick Encore. However, it is still accessible from the selected car via links, so may be relevant.

Inoperative in All Speeds

  1. Ignition OFF, disconnect the harness connector at the R10 Cooling Fan Resistor.
  2. Verify a test lamp illuminates between the ground circuit terminal 1 and B+.
    • If the test lamp does not illuminate 
    1. Ignition OFF, remove the test lamp.
    2. Test for less than 2 Ω in the 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 the test lamp illuminates 
  3. Test or replace the G10 Cooling Fan Motor. Replace the cooling fan fuses if necessary.

Low, Medium, or High Speed Inoperative

  1. Ignition OFF.
  2. Disconnect the following cooling fan relays, ignition ON:
    • KR20C Cooling Fan Low Speed Relay
    • KR20D Cooling Fan High Speed Relay
    • KR20E Cooling Fan Speed Control Relay
    • KR20F Cooling Fan Relay
    • KR20P Cooling Fan Medium Speed Relay
  3. Verify a test lamp illuminates between ground and each of the cooling fan relay B+ circuit terminals listed below:
    • KR20C Cooling Fan Low Speed Relay terminal 30/3
    • KR20D Cooling Fan High Speed Relay terminal 30/3
    • KR20P Cooling Fan Medium Speed Relay terminal 30/3
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF, remove the test lamp.
    2. Test for less than 2 Ω in the appropriate relay 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. Ignition OFF, disconnect the harness connector at the R10 Cooling Fan Resistor.
    2. Test for infinite resistance between the appropriate relay controlled output circuit terminal listed below and ground:
      • KR20C Cooling Fan Low Speed Relay terminal 87/5
      • KR20D Cooling Fan High Speed Relay terminal 87/5
      • KR20P Cooling Fan Medium Speed Relay terminal 87/5
      • If less than infinite resistance, repair the short to ground in the circuit.
      • If infinite resistance, test or replace the G10 Cooling Fan Motor, replace the fuse as necessary.
    • If the test lamp illuminates 
  4. Verify a test lamp illuminates between the KR20F Cooling Fan Relay output circuit terminal 87/5 and B+.
    • If the test lamp does not illuminate 
    1. Ignition OFF, remove the test lamp.
    2. Test for less than 2 Ω in the 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 the test lamp illuminates 
  5. Ignition OFF, Install the KR20F Cooling Fan Relay, ignition ON.
  6. Verify a test lamp illuminates between each of the cooling fan relay ignition circuit terminals listed below and ground:
    • KR20C Cooling Fan Low Speed Relay terminal 86/1
    • KR20E Cooling Fan Speed Control Relay terminal 85/2 and 30/3
    • If the test lamp does not illuminate at each terminal 
    1. Ignition OFF, remove the test lamp.
    2. Test for less than 2 Ω between the appropriate relay ignition circuit terminal and the fuse.
      • 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 illuminates at each terminal 
  7. Command the cooling fan ON at low speed with a scan tool.
  8. Verify a test lamp illuminates between B+ and each of the relay control circuit terminals listed below:
    • KR20C Cooling Fan Low Speed Relay terminal 85
    • KR20E Cooling Fan Speed Control Relay terminal 86
    • If the test lamp does not illuminate 
    1. Ignition OFF, remove the test lamp and disconnect the KR20F Cooling Fan Relay.
    2. Test for less than 2 Ω between the KR20F Cooling Fan Relay terminal 30/3 and the relay control circuit terminals listed below:
      • KR20C Cooling Fan Low Speed Relay terminal 85
      • KR20E Cooling Fan Speed Control Relay terminal 86
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the KR20F Cooling Fan Relay.
    • If the test lamp illuminates 
  9. Ignition OFF, install the KR20E Cooling Fan Speed Control Relay, ignition ON.
  10. Command the cooling fan ON at low speed with a scan tool.
  11. Verify a test lamp illuminates between the KR20D Cooling Fan High Speed Relay ignition circuit terminal 85/1 and ground.
    • If the test lamp does not illuminate 
    1. Ignition OFF, remove the test lamp and disconnect the KR20E Cooling Fan Speed Control Relay.
    2. Test for less than 2 Ω between the KR20D Cooling Fan High Speed Relay terminal 85/1 and KR20E Cooling Fan Speed Control Relay terminal 87/5.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the KR20E Cooling Fan Speed Control Relay.
    • If the test lamp illuminates 
  12. Ignition OFF, install all of the previously removed cooling fan relays. Disconnect the harness connector at the R10 Cooling Fan Resistor, ignition ON.
  13. Command the cooling fan ON at high speed with a scan tool.
  14. Verify a test lamp illuminates between ground and each of the R10 Cooling Fan Resistor circuit terminals listed below:
    • R10 Cooling Fan Resistor low speed circuit terminal 2
    • R10 Cooling Fan Resistor medium speed circuit terminal 3
    • R10 Cooling Fan Resistor high speed circuit terminal 4
    • If the test lamp does not illuminate at each terminal 
    1. Ignition OFF, remove the test lamp.
    2. Disconnect the appropriate relay from the list below:
      • KR20C Cooling Fan Low Speed Relay
      • KR20D Cooling Fan High Speed Relay
      • KR20P Cooling Fan Medium Speed Relay
    3. Test for less than 2 Ω in the relay controlled output circuit, end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, test or replace the relay.
    • If the test lamp illuminates at each terminal 
  15. Test or replace the G10 Cooling Fan Motor.
scientia non olet · About LEMON Manuals