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Russ 1/8/2022

2003 Ford Taurus SEL 6 Cyl 3.00L

Body & Interior

Heat & defrost works around town, but not on long trips

2003 Ford Taurus with only 38,000 original miles. Belonged to my mother, but did not get driven for 10 to 11 months. Before putting it back on the road the PCM had to be replaced due to starting issues. Have been driving it with no problem for past month. On a recent trip from CT to VA we had no noticeable problem on trip to VA (mild December day and clear), but on way back to CT (rain on and off and colder) we developed a problem with no noticeable heat and no defrost (had to keep front window cracked to clear windshield) - which made for a cold drive home. After returning home the next day and since, there has been no noticeable problem with the heat or defrost. Would like to correct the problem before the next trip.

1 Answer


Jimm 1/15/2022

First step - check the vacuum hoses condition - to and from the blend door actuator. Next, check that the heater core is in the open position by using the shut off valve and turning it to open.
Next, there may be a malfunction in the direction door the directs the air flow in the dash.

Check for a lever may have become loose or separated. There may be a malfunctioning servo motor not directing the door to move to the heater position. Start the diagnosis by checking the vacuum hoses, and then the shut off valve on the heater core.


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