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Home >> Chevrolet >> 2015 >> Cruze LT, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 18 (Wiring Systems And Power Management - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC B144A: Run Power Relay (Trax) >> 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.

Diagnostic A

  1. Ignition OFF and all vehicle systems OFF, disconnect the X2 harness connector at the K33 HVAC Control Module.
  2. Connect a test lamp between the ignition circuit terminal 2 and ground. Ignition ON.
  3. Verify the test lamp turns ON and OFF when commanding the Auxiliary Ignition Run Relay On and Off with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module, the KR32E Blower Motor Relay, and the KR74 Ignition Run Relay.
    2. Test for infinite resistance between the ignition circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the ignition circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
    • If the test lamp is always ON 
    1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module, ignition ON.
    2. Test for less than 1 V between the ignition circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K9 Body Control Module.
    • If the test lamp turns ON and OFF 
  4. Test or replace the K33 HVAC Control Module.

Diagnostic B

  1. Ignition OFF and all vehicle systems OFF, disconnect the KR32E Blower Motor Relay and the KR74 Ignition Run Relay. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 10 Ω between the ground circuits listed below and ground.
    • KR32E Blower Motor Relay - Ground circuit terminal 1
    • KR74 Ignition Run Relay - Ground circuit terminal 2
    • 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 
  3. Ignition ON, connect a test lamp between the control circuits listed below and ground.
    • KR32E Blower Motor Relay - Control circuit terminal 2
    • KR74 Ignition Run Relay - Control circuit terminal 1
  4. Verify the test lamp turns ON and OFF when commanding the Auxiliary Ignition Run Relay On and Off with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module and 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
    3. 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 K9 Body Control Module.
    • If the test lamp is always ON 
    1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K9 Body Control Module, ignition ON.
    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, replace the K9 Body Control Module.
    • If the test lamp turns ON and OFF 
  5. Test or replace the KR32E Blower Motor Relay or the KR74 Ignition Run Relay.
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