Circuit/System Testing
- Vehicle OFF and all vehicle systems OFF, disconnect the KR5 Rear Defogger Relay. It may take up to 2 minutes for all vehicle systems to power down.
- Test for less than 10 Ω between the ground circuit terminal 85 and ground.
- If 10 Ω or greater
- Vehicle OFF.
- 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
- Vehicle in Service Mode.
- Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.
- If the test lamp does not illuminate
- Replace the X50A Fuse Block-Underhood
- If the test lamp illuminates
- Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.
- Verify the test lamp turns ON and OFF pressing the rear window defogger switch.
- If the test lamp is always OFF
- Vehicle OFF, remove the test lamp, disconnect the harness connector at the K33 HVAC Control Module.
- 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
- 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 the test lamp is always ON
- Vehicle OFF, remove the test lamp, disconnect the harness connector at the K33 HVAC Control Module, Vehicle in Service Mode.
- 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
- Verify that a test lamp does not illuminate between the control circuit terminal 87 and ground.
- If the test lamp illuminates
Repair the short to voltage on the control circuit
- If the test lamp does not illuminate
- If the test lamp illuminates
- Vehicle OFF and all vehicle systems OFF, disconnect the X2 harness connector at the E18 Rear Defogger Grid. It may take up to 2 minutes for all vehicle systems to power down.
- Test for less than 10 Ω between the ground circuit terminal 1 and ground.
- If 10 Ω or greater
- Vehicle OFF.
- 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
- Connect the X2 harness connector at the E18 Rear Defogger Grid.
- Vehicle in Service Mode, connect a 30 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87.
- Verify the E18 Rear Defogger Grid is activated.
- If the E18 Rear Defogger Grid does not activate
- Vehicle OFF, remove the jumper wire, disconnect the X1 harness connector at the E18 Rear Defogger Grid.
- 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
- 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 E18 Rear Defogger Grid.
- If the E18 Rear Defogger Grid activates
- Test or replace the KR5 Rear Defogger Relay.