Test M: Temperature Control Is Inoperative/Does Not Operate Correctly

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

M1-M2:

M3-M4:

M5-M7:

M7-M9:

M9-M11:

M11-M12:

M12-M13:

M13-M14:

M14-M15:

M15-M16:

M16-M17:

M17-M18:

Normal Operation
Under normal operation, to rotate the blend door actuator clockwise, the electronic manual temperature control (EMTC) module or electronic automatic temperature control (EATC) 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 or EATC module reverses the voltage and ground circuits.

The blend door actuator feedback resistors are supplied a ground from the EMTC module or EATC module by the blend door actuator return circuits and a 5-volt reference voltage on the blend door actuator reference circuits. The EMTC module or EATC 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
- LH blend - CH238 (YE/OG)
- RH blend - CH213 (BN/GN)

Door actuator feed B circuits
- LH blend - CH239 (BU/WH)
- RH blend - CH212 (BU/OG)

Door actuator return circuits
- LH blend - RH111 (GY/BU)
- RH blend - RH111 (GY/BU)

Door actuator reference circuits
- LH blend - LH111 (BN/WH)
- RH blend - LH111 (BN/WH)

Door actuator feedback circuits
- LH blend - VH440 (BU/BN)
- RH blend - VH441 (WH/BN)

Possible Causes
- An open, short to voltage, ground or together in door actuator open, close, return, reference or feedback circuits
- Blend door actuator
- EATC module
- EMTC module
- Stuck or bound linkage or door