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Home >> Ford >> 2007 >> E 250 V8-5.4L >> Repair and Diagnosis >> Heating and Air Conditioning >> Testing and Inspection >> Pinpoint Tests >> Test F: Temperature Control Is Inoperative/Does Not Operate Correctly
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Test F: Temperature Control Is Inoperative/Does Not Operate Correctly

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


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Normal Operation
Under normal operation, the temperature blend door actuator is supplied voltage on circuit 489 (PK/BK) and ground on circuit 57 (BK). As the temperature selection changes it varies the voltage on circuit 437 (YE/LG) to the temperature blend door actuator. The temperature control potentiometer receives reference voltage from the temperature blend door actuator through circuit 436 (RD/LG). Ground for the temperature control potentiometer is supplied from the temperature blend door actuator through circuit 438 (RD/WH).

Possible Causes
- Fuse(s)
- An open, short to voltage, ground or together in circuits 57 (BK), 436 (RD/LG), 437 (YE/LG), 438 (RD/WH) or 489 (PK/BK)
- Temperature blend door actuator
- Temperature control potentiometer
- Stuck or bound linkage or door
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