45 acp

I have searched and can't find a definitive answer. I have had this 98 Taurus for a couple years and the heat/defrost has never worked well at all. I am driving it a lot more recently as a dd so I figured I'd try to fix it.

I have replaced the blower motor and cleaned the cabin air filter so far. Running the heat or defrost at full blast gets virtually no air moving from any vent, not enough to blow out a match.

The blend door actuator moves when I turn the hot/cold knob and the door above the blower motor opens and shuts when turned from off to whatever.

Is there another door somewhere diverting the airflow or is the blend door likely broken? This thing is really getting me

Bert

The blend door only changes the temperature. There's probably a vacuum leak and the other flaps don't move as set. If most of the air blows toward the windshield, Look for a vacuum leak most likely under the hood.

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Bert

45 acp

I couldn't find a vac leak under the hood anywhere. Is there a vacuum reservoir somewhere? Maybe that's bad. It could have a vac leak, it has always idled high.

Is there a diagram of the heating system anywhere? I didn't see one on Google.

Bert

The reservoir is under the hood. Here's the schematic for it. The vacuum tank and check valve are under the hood.

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Bert

45 acp

Thanks Bert, that should help.

wizenhymer

I am having the exact same problem with a 98 taurus.

Blower changed, intake airway clear, recirculate door working fine, BUT no airflow.

Just barely enough to be felt at any outlet in any mode.

I have also verified that the blend door actuator IS following commands (I can see the lever moving), but there is just no air going through this thing.

Hoping to get an update from 45 acp. Did you find a fix?

wizenhymer

The blower motor wiring was reversed. It hit me in the middle of the night that the blower might be running backwards. So I pulled it out and checked whether it was turning the right way to get air through the vents. It wasn't.

It came that way from Auto Zone. This was the less expensive model, "Continental part number PM3923", with the connector on a pigtail. It was easy to reverse the pins on this connector.

I was able to pull the oval shaped red rubber holder out of the connector shell from the pin side, then used the small screwdriver on my leatherman to release the retaining finger (towards the middle) on each pin. I then had to re-bend the retaining fingers since they were now flat, and put them back into the shell in the opposite order. Inserted pins until I heard the click of the retaining finger and verified they couldn't back out. Then I just pushed the rubber holder back in, connected it up, mounted it, and *presto*, I had air flow.

The way it was originally wired, I had a blower to exhaust heat (or cooling) from the vehicle!! That's why the airflow felt weak; it was drawing air into the vents rather than pushing it out!

Bert

Glad to hear taht you got it fixed. Thanks for the update.

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Bert