Temperature Door/Valve Actuator Diagnosis - Electronic Touch Climate Control

Fig. 2 Temperature actuator terminal identification. Estate Wagon:

1. Check temperature door for binding, and to ensure proper adjustment. Check actuator arm for blockage. Check actuator harness connections for looseness or corrosion. Correct as needed. Remove actuator connector.
2. Apply 12 volts DC to terminals A and B, Fig. 2, of actuator for 2-3 seconds. Observe actuator arm movement. Reverse test leads to terminals A & B, and repeat test. Observe actuator arm movement. If arm moves in both directions, drive circuit is good. If drive circuit is good, proceed to step 3. If actuator runs but arm does not move, actuator drive is stripped and actuator must be replaced.
3. Check resistance at terminals C and D of actuator using suitable ohmmeter. Reading should be 1.1k ohms between 68-86°F. If resistance is at specification, proceed to step 4. If resistance reading is at infinity, a broken resistor strip may be at fault. Replace actuator.
4. Move actuator arm to calibration point by applying 12 volts DC to terminals A and B of actuator, Fig. 2. Measure resistance at this point (terminals C and F) using suitable ohmmeter. If reading is 670 ohms, actuator is good. Proceed to step 5. If any other readings are obtained, a failed feedback circuit is indicated and actuator must be replaced.
5. Check continuity of actuator to control panel wiring. Correct any breaks. If no faults are found in wiring, control panel is defective and must be replaced.