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

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

E1-E2:

E3-E5:

E5-E7:

E7-E9:

E9-E11:

Normal Operation
Under normal operation, voltage is supplied to the blend door actuator through circuit CBP27 (GN/BN). The blend door actuator is grounded through circuit GD161 (BK/YE). A 5-volt reference voltage and ground are provided by the blend door actuator to the temperature control through circuit CH449 (BU/OG) and RH449 (GY/OG). The temperature control feeds the desired position to the blend door actuator through circuit VH450 (BN/WH).

Possible Causes
- Fuse
- An open in circuit GD161 (BK/YE), CH449 (BU/OG), VH450 (BN/WH), RH449 (GY/OG) or CBP27 (GN/BN)
- A short to ground in circuit CH449 (BU/OG) or VH450 (BN/WH)
- A short to voltage in circuit CH449 (BU/OG) or VH450 (BN/WH)
- A short together in circuits CH449 (BU/OG), VH450 (BN/WH) or RH449 (GY/OG)
- Temperature control potentiometer
- Temperature blend door actuator
- Stuck or bound linkage or door