Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnosis Procedure
Regarding Wiring Diagram information, refer to WIRING DIAGRAM .
- CHECK INPUT 1 - 5 SYSTEM CIRCUIT FOR OPEN
- Turn ignition switch OFF.
- Disconnect BCM connector M18 and combination switch connector.
- Check continuity between BCM connector M18 and combination switch connector M28.
Combination switch signal BCM Combination switch Continuity Connector Terminal Connector Terminal INPUT 1 M18 38 M28 8 Yes INPUT 2 39 6 INPUT 3 36 5 INPUT 4 37 3 INPUT 5 33 1
Is the inspection result normal?
YES
GO TO STEP 2.
NO
Repair or replace harness or connectors.
- CHECK INPUT 1 - 5 SYSTEM CIRCUIT FOR SHORT
Check continuity between BCM connector M18 and ground.
Combination switch signal BCM Ground Continuity Connector Terminal INPUT 1 M18 38 No INPUT 2 39 INPUT 3 36 INPUT 4 37 INPUT 5 33 Is the inspection result normal?
YES
GO TO STEP 3 .
NO
Repair or replace harness or connectors.
- CHECK BCM OUTPUT VOLTAGE
- Connect BCM connector M18 and combination switch connector.
- Turn ignition switch ON.
- Check voltage between BCM connector M18 and ground.
Combination switch signal BCM Ground Voltage Connector Terminal INPUT 1 M18 38 - Refer to REFERENCE VALUE . INPUT 2 39 INPUT 3 36 INPUT 4 37 INPUT 5 33
Is the inspection result normal?
YES
Replace the combination switch. Refer to REMOVAL AND INSTALLATION .
NO
Replace BCM. Refer to REMOVAL AND INSTALLATION .
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.