Circuit/System Testing

Ignition OFF and all vehicle systems OFF, disconnect the X1 harness connector at the K33 HVAC control module. 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 23 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
Ignition ON, connect a DMM between the control circuit terminal 17 and the ground circuit terminal 23.
Command the defog indicator ON and OFF with a scan tool.
Test for 9 V with the defog indicator commanded OFF, and 12 V with the defog indicator commanded ON.
- If always 9 V
1. Ignition OFF, disconnect the X5 harness connector at the K9 body control module.
2. Test for infinite resistance between the control circuit terminal 17 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 K9 body control module.
- If always 12 V
1. Ignition OFF, disconnect the X1 harness connector at the K9 body control module, ignition ON.
2. Test for less than 1 V between the control circuit terminal 17 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.
- Go to next step: If 9 V when OFF and 12 V when ON
Test or replace the K33 HVAC control module.