Pinpoint Test 6: Temperature Control Is Inoperative/Does Not Operate Correctly

PINPOINT TEST 6: TEMPERATURE CONTROL IS INOPERATIVE/DOES NOT OPERATE CORRECTLY

Normal Operation

To rotate the blend door actuator clockwise, the electronic manual temperature control (EMTC) module supplies voltage to the blend door actuator motors through the door actuator feed A circuits, and supplies ground through the door actuator feed B circuits. To rotate the blend door actuator counterclockwise, the EMTC module reverses the voltage and ground circuits.The blend door actuator feedback resistors are supplied a ground from the EMTC module by the blend door actuator return circuits and a 5-volt reference voltage on the blend door actuator reference circuits. The EMTC module reads the voltage on the blend door actuator feedback circuits to determine the blend door actuator position by the position of the actuator feedback resistor wiper arm.

- Door actuator feed A circuits (EMTC module) blend (Y/O)
- Door actuator feed B circuits (EMTC module) blend (L/W)
- Door actuator return circuits (EMTC module) blend (GY/L)
- Door actuator reference circuits (EMTC module) blend (GY/L)
- Door actuator feedback circuits (EMTC module) blend (GY/L)





Possible Causes
- Wiring, terminals or connectors
- Blend door actuator
- EMTC module
- Stuck or damaged linkage or door

Diagnostic Procedure