Even when the A/C is all the way off and turned to the lowest fan setting, air still comes from the vent. Is this normal with our trucks? Or is it a possible electrical problem with the relays to turn the A/C off?

 

There are no relays for the HVAC blower. Check the switch.




Component Testing

 

If the selector switch is in a position other than "off", the blower motor runs. Lowest fan setting the fan will idle. That's just how it is. If you put the selector on defrost, and you're getting significant airflow to your feet, then you have a problem with the selector.

But ford has no "fan off" selection for the fan If you're on a/c, the fan will idle to continue flow through the hvac box.

 

HOT-COLD selector is normally "manual" --- a cable.

The other controls (e.g Vent) are vacuum lines normally.................vacuum leaks are very common on these old trucks ........