Circuit/System Testing
- Ignition/Vehicle & All vehicle systems - Off
- Disconnect the electrical connector: X1 @ X53A Fuse Block - Rear Body
- Test for less than 10 ohms between the test points: Ground circuit terminal 27 X1 & Ground
- If 10 ohms or greater
- Ground Connection - Disconnect
- Test for less than 2 ohms between the test points: Ground circuit terminal 27 X1 & 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
- Connect the electrical connector: X1 @ X53A Fuse Block - Rear Body
- Disconnect the electrical connector: X2 @ K33 HVAC Control Module
- Ignition - On/Vehicle - In Service Mode
- Momentarily connect a 3 A fused jumper wire between the test points: Control circuit terminal 19 X2 & B+
Verify the component turns On and Off when connecting and disconnecting the jumper wire: E18 Rear Defogger Grid
- If the component does not turn On and Off
- Ignition/Vehicle - Off & Remove - Jumper wire(s)
- Disconnect the electrical connector: X2 @ X53A Fuse Block - Rear Body
- Ignition - On/Vehicle - In Service Mode
- Test for less than 1 V between the test points: Control circuit terminal 19 X2 @ Control module harness & Ground
- If 1 V or greater - Repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
- Ignition/Vehicle - Off
- Test for infinite resistance between the test points: Control circuit terminal 19 X2 @ Control module harness & Ground
- If less than infinite resistance - Repair the short to ground on the circuit.
- Go to next step: If infinite resistance
- Test for less than 2 ohms between the test points: Control circuit terminal 19 X2 @ Control module harness & Terminal 34 X2 @ Fuse Block Harness
- If 2 ohms or greater - Repair the open/high resistance in the circuit.
- If less than 2 ohms - Test or replace the component: X53A Fuse Block - Rear Body
- Go to next step: If the component turns On and Off
- Replace the component: K33 HVAC Control Module
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.