Circuit/System Testing

Ignition 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
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.
- Go to next step: If less than 10 Ω
Engine Running.
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
- Go to next step: 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 when pressing the rear window defogger switch.
- If the test lamp is always OFF
1. Ignition OFF, disconnect the 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.
  - Go to next step: 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 K33 HVAC control module.
- If the test lamp is always ON
1. Ignition OFF, disconnect the harness connector at the K33 HVAC 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 K33 HVAC control module.
- Go to next step: 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
- Go to next step: If the test lamp does not illuminate
Ignition OFF and all vehicle systems OFF, connect the KR5 Rear Defogger Relay and disconnect the X2 harness connector at the E18L Rear Defogger Grid-Left. 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 A X2 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.
- Go to next step: If less than 10 Ω
Connect the X2 harness connector at the E18L Rear Defogger Grid-Left.
Disconnect the X1 harness connector at the E18R Rear Defogger Grid-Right.
Connect a test lamp between the control circuit terminal A X1 and ground.
Verify the test lamp turns ON and OFF when pressing the rear window defogger switch.
- If the test lamp is always OFF
1. Ignition OFF, disconnect the KR5 Rear Defogger Relay.
2. Test for infinite resistance between the control circuit and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - Go to next step: 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, test or replace the KR5 Rear Defogger Relay.
- Go to next step: If the test lamp turns ON and OFF
Test or replace the E18L Rear Defogger Grid - Left or E18R Rear Defogger Grid - Right.