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.
Component Inspection
- Check actuator motor.
- Ignition "OFF"
- Disconnect Intake Potentiometer.
- Verify that the temperature actuator operates to the fresh position when connecting 12V to the terminal "3" and grounding terminal "4".
- Verify that the temperature actuator operates to the recirculation position when the connections are reversed.
- Does the actuator work properly?
YES
- Check potentiometer.
NO
- Substitute with a known-good actuator and check for proper operation. If the problem is corrected, replace actuator and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.
- Check potentiometer
- Ignition "ON"
- Connect Intake Potentiometer.
- Measure voltage between terminal "5" and "6" of Intake potentiometer while operating Intake switch.
Specification : Refer the specifications
TERMINAL VOLTAGE REFERENCEDoor position Voltage (5-6) Error detecting Fresh 0.3 ± 0.15V Low voltage : 0.08V or less Recirculation 4.7 ± 0.15V High voltage : 4.9V or more Specifications : Voltage value of Intake potentiometer as a function of position of Intake.
- Is the measured voltage within specifications?
YES
- Check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.
NO
- Substitute with a known-good actuator and check for proper operation. If the problem is corrected, replace actuator and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.
- Check Heater & A/C controller.
- Engine "ON"
- Connect Heater & A/C controller.
- Measure voltage between terminal "22" and "23" of Heater & A/C controller while operating the Intake switch.
Specification : Approx. 12V
- Is the measured voltage within specifications?
YES
- Check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.
NO
- Substitute with a known-good Heater & A/C controller and check for proper operation.
If the problem is corrected, replace Heater & A/C controller and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.
NO RELATED
Use the Manual With the Right Hardware
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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.