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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.

Blower Motor Circuit Test

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the R3 Blower Motor Resistor. It may take up to 10 min for all vehicle systems to power down.
  2. Place the blower motor switch in the high speed position.
  3. Test for less than 10 Ω between the control circuit terminal D and ground.
    • If 10 Ω or greater 
    1. Ignition OFF, disconnect the X1 harness connector at the K33 HVAC Control Module.
    2. Test for greater than 2 Ω between the ground circuit terminal 1 and ground.
      • If less than 2 Ω, replace the K33 HVAC Control Module.
      • If greater than 2 Ω
    3. 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 less than 10 Ω 
  4. Ignition OFF, connect the harness connector at the R3 Blower Motor Resistor and disconnect the harness connector at the M8 Blower Motor.
  5. Test for less than 10 Ω between the control circuit terminal 1 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF, disconnect the harness connector at the R3 Blower Motor Resistor.
    2. 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, test or replace the R3 Blower Motor Resistor.
    • If less than 10 Ω 
  6. Ignition OFF, disconnect the KR32E Blower Motor Relay.
  7. Test for less than 10 Ω between the ground circuit terminal R4-1 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF.
    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 less than 10 Ω 
  8. Ignition ON.
  9. Verify a test lamp illuminates between the B+ circuit terminal R4-3 and ground.
    • 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 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, remove the test lamp.
    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
    3. Test for infinite resistance between the M8 Blower Motor control circuit terminal 2 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    4. Test the KR32E Blower Motor Relay, refer to Component Testing.
      • If the relay tests OK, test or replace the M8 Blower Motor.
      • If the relay does not test OK, replace the KR32E Blower Motor Relay.
    • If the test lamp illuminates 
  10. Verify a test lamp illuminates between the control circuit terminal R4-2 and the ground circuit terminal R4-1.
    • If the test lamp does not illuminate 

      Repair the open/high resistance in the control circuit.

    • If the test lamp illuminates 
  11. Connect the harness connector at the M8 Blower Motor.
  12. Install a 40 A fused jumper wire between the B+ circuit terminal R4-3 and the control circuit terminal R4-5, ignition ON.
  13. Verify the M8 Blower Motor operates.
    • If the M8 Blower Motor does not operate 
    1. Ignition OFF, remove the jumper wire and disconnect the harness connector at the M8 Blower Motor.
    2. 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, test or replace the M8 Blower Motor.
    • If the M8 Blower Motor operates 
  14. Refer to Testing for Intermittent Conditions and Poor Connections .

Blower Motor Switch Circuit Test

  1. Ignition OFF, disconnect the harness connector at the R3 Blower Motor Resistor.
  2. Test for less than 10 Ω between each control circuit terminal listed below and ground with the blower switch in the appropriate position.
    • Blower speed 1 terminal E
    • Blower speed 2 terminal A
    • Blower speed 3 terminal B
    • Blower speed 4 terminal D
    • If 10 Ω or greater 
    1. Ignition OFF, disconnect the X1 harness connector at the K33 HVAC Control Module.
    2. 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 K33 HVAC Control Module.
    • If less than 10 Ω 
  3. Test or replace the R3 Blower Motor Resistor.

Blower Motor Always ON Circuit Test

  1. Ignition OFF, disconnect the harness connector at the R3 Blower Motor Resistor.
  2. Place the blower motor switch in the OFF position.
  3. Test for infinite resistance between each control circuit terminal listed below and ground:
    • Blower speed 1 terminal E
    • Blower speed 2 terminal A
    • Blower speed 3 terminal B
    • Blower speed 4 terminal D
    • If less than infinite resistance 
    1. Disconnect the X1 harness connector at the K33 HVAC Control Module.
    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 K33 HVAC Control Module.
    • If infinite resistance 
  4. Ignition OFF, disconnect the harness connector at the M8 blower motor.
  5. Test for infinite resistance between the control circuit terminal 1 and ground.
    • If less than infinite resistance 

      Repair the short to ground on the circuit

    • If infinite resistance 
  6. Refer to Testing for Intermittent Conditions and Poor Connections .
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