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Circuit/System Testing

Test 1

  1. Ignition/Vehicle - Off
  2. Disconnect the electrical connector: K33 HVAC Control Module
  3. Ignition - On / Vehicle - In Service Mode
  4. Verify the component is not activated: E18 Rear Defogger Grid
    • If the component is On 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: X2 @ K9 Body Control Module
    3. Test for infinite resistance between the test points: Signal circuit terminal 2 @ K33 HVAC Control Module & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: K9 Body Control Module
    • Go to next step: If the component is Off 
  5. Connect a 3 A fused jumper wire between the test points: Signal circuit terminal 2 & Ground
  6. Verify the component activates: E18 Rear Defogger Grid
    • If the component is Off 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: X2 @ K9 Body Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Signal circuit terminal 2 & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    5. Ignition/Vehicle - Off
    6. Test for less than 2 ohms between the test points: Signal circuit terminal 2 @ K33 HVAC Control Module & Terminal 14 X2 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K9 Body Control Module
    • Go to next step: If the component is On 
  7. Replace the component: K33 HVAC Control Module

Test 2

    NOTE:

    It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

  1. Ignition/Vehicle & All vehicle systems - Off
  2. Remove the component: KR5 Rear Defogger Relay
  3. Test for less than 10 ohms between the test points: Ground circuit terminal 85 & Ground
    • If 10 ohms or greater 
    1. Ground Connection - Disconnect
    2. Test for less than 2 ohms between the test points: Ground circuit terminal 85 & Ground Connection
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Repair the open/high resistance in the ground connection.
    • Go to next step: If less than 10 ohms 
  4. Connect a test lamp between the test points: Control circuit terminal 86 Ground circuit terminal 85
  5. Ignition - On / Vehicle - In Service Mode
  6. Operate the component: Rear Defogger Switch - Pressed

    Verify the test lamp turns On and Off.

    • If the test lamp is always Off 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: K9 Body Control Module
    3. Test for infinite resistance between the test points: Control circuit terminal 86 @ Relay Socket & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    4. Test for less than 2 ohms between the test points: Control circuit terminal 86 @ Relay Socket & Terminal 11 X5 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K9 Body Control Module
    • If the test lamp is always On 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: K9 Body Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control circuit terminal 86 @ Relay Socket & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component: K9 Body Control Module
    • Go to next step: If the test lamp turns On and Off 
  7. Verify a test lamp turns On between the test points: B+ circuit terminal 30 & Ground
    • If the test lamp does not turn On and the circuit fuse is OK 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Test for less than 2 ohms between the test points: B+ circuit terminal 30 @ Relay Socket & Output terminal @ Fuse
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Verify the fuse is OK and there is voltage at the fuse.
    • If the test lamp does not turn On and the circuit fuse is open 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Test for infinite resistance between the test points: B+ circuit terminal 30 & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Disconnect the electrical connector: X1 & X2 @ E18 Rear Defogger Grid
    4. Test for infinite resistance between the test points: Control circuit terminal 87 @ Relay Socket & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    5. Replace the component: Fuse
    6. Install the component: KR5 Rear Defogger Relay
    7. Connect a test lamp between the test points: Control circuit terminal 1 X1 & Ground circuit terminal 1 X2
    8. Ignition - On / Vehicle - In Service Mode
    9. Rear Defogger Switch - Pressed

      Verify the test lamp turns On and Off.

      • If the test lamp does not turn On and Off - Test or replace the component: KR5 Rear Defogger Relay
      • If the test lamp turns On and Off - Test or replace the component: E18 Rear Defogger Grid
    • Go to next step: If the test lamp turns On 
  8. Momentarily connect a 30 A fused jumper wire between the test points: B+ circuit terminal 30 & Control circuit terminal 87

    Verify the component does not turn On and Off when connecting and disconnecting the jumper wire: E18 Rear Defogger Grid

    • If the component turns On and Off 

      Test or replace the component: KR5 Rear Defogger Relay

    • Go to next step: If the component does not turn On and Off 
  9. Ignition/Vehicle & All vehicle systems - Off
  10. Install the component: KR5 Rear Defogger Relay
  11. Disconnect the electrical connector: E18 Rear Defogger Grid
  12. Test for less than 10 ohms between the test points: Ground circuit terminal 1 X2 & Ground
    • If 10 ohms or greater 
    1. Ground Connection - Disconnect
    2. Test for less than 2 ohms between the test points: Ground circuit terminal 1 X2 @ Component harness & Ground Connection
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Repair the open/high resistance in the ground connection.
    • Go to next step: If less than 10 ohms 
  13. Connect a test lamp between the test points: Control circuit terminal 1 X1 & Ground circuit terminal 1 X2
  14. Ignition - On / Vehicle - In Service Mode
  15. Operate the component: Rear Defogger Switch - Pressed

    Verify the test lamp turns On and Off.

    • If the test lamp is always Off 

      Repair the open/high resistance in the circuit: Control Circuit

    • If the test lamp is always On 

      Repair the short to voltage on the circuit: Control Circuit

    • Go to next step: If the test lamp turns On and Off 
  16. Test or replace the component: E18 Rear Defogger Grid

Test 3

  1. Ignition/Vehicle - Off
  2. Disconnect the electrical connector: K33 HVAC Control Module
  3. Connect a test lamp between the test points: Control circuit terminal 3 & Ground
  4. Ignition - On / Vehicle - In Service Mode
  5. Verify the test lamp does not turn On.
    • If the test lamp turns On 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: X1 or X3 @ K9 Body Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control circuit terminal 3 & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component: K9 Body Control Module
    • Go to next step: If the test lamp does not turn On 
  6. Connect a 3 A fused jumper wire between the test points: Signal circuit terminal 2 & Ground
  7. Verify the test lamp turns On.
    • If the test lamp does not turn On 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: X1 or X3 @ K9 Body Control Module
    3. Test for infinite resistance between the test points: Control circuit terminal 3 @ K33 HVAC Control Module & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    4. Ignition/Vehicle - Off & Remove - Test lamp
    5. Test for less than 2 ohms between the test points:
      • {Without KL9} Control circuit terminal 3 @ K33 HVAC Control Module & Terminal 23 X1 @ Control module harness
      • {With KL9} Control circuit terminal 3 @ K33 HVAC Control Module & Terminal 19 X3 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K9 Body Control Module
    • Go to next step: If the component is On 
  8. Replace the component: K33 HVAC Control Module
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