Test E: The Temperature Control Is Inoperative/Does Not Operate Correctly

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

E1:

E1-E3:

E4-E5:

E6-E7:

E8-E10:

E10-E11:

Normal Operation
Under normal operation, voltage is supplied to the blend door actuator through circuit 1003 (GY/YE). The blend door actuator is grounded through circuit 57 (BK). A 5-volt reference voltage and ground are provided by the blend door actuator to the temperature control through circuit 436 (RD/LG) and 438 (RD/WH). The temperature control feeds the desired position to the blend door actuator through circuit 437 (YE/LG).

Possible Causes
- Fuse
- An open in circuit 57 (BK), 436 (RD/LG), 437 (YE/LG), 438 (RD/WH) or 1003 (GY/YE)
- A short to ground in circuit 436 (RD/LG) or 437 (YE/LG)
- A short to voltage in circuit 436 (RD/LG) or 437 (YE/LG)
- A short together in circuits 436 (RD/LG), 437 (YE/LG) or 438 (RD/WH)
- Temperature control potentiometer
- Temperature blend door actuator
- Stuck or bound linkage or door