Heat/AC question

[virgamanda]

What would cause the air to blow on the floor at all selections. The air blow out of the appropiate vents with each selected mode, but also blows on the floor pretty strong on all modes. Not much of a problem, just causes my feet to sweat like crazy. How can this be corrected.

[shorod]

What year is your Explorer? Does it have the manual HVAC controls, or the electronic controls? If manual controls (3 dials), the air diverter servos are probably vacuum controlled. If the electronic controls, the diverter servos are electric, and the control head performs a self test and can display codes if it recognizes a problem.

-Rod

[virgamanda]

Originally Posted by shorod

What year is your Explorer? Does it have the manual HVAC controls, or the electronic controls? If manual controls (3 dials), the air diverter servos are probably vacuum controlled. If the electronic controls, the diverter servos are electric, and the control head performs a self test and can display codes if it recognizes a problem.

-Rod

It is a 97 Explorer 4.0 4X4 with the 3 dial manual control.

[shorod]

There is a "Floor/Panel Vacuum Door Motor" that controls a door to blend between floor and panel. It looks like if that motor were getting vacuum to both ports, it would put the door in the middle position, distributing partial air flow to the floor at all settings. I suppose a leaky vacuum motor diaphragm could cause this, as could a faulty heater control switch. If you set the controls to "floor," does the amount of floor airflow seem to increase?

If you'd like me to send you the vacuum and wiring diagram for the HVAC system, send me a private message with an e-mail address for you that can accept PDF attachments.

-Rod

[virgamanda]

Originally Posted by shorod

There is a "Floor/Panel Vacuum Door Motor" that controls a door to blend between floor and panel. It looks like if that motor were getting vacuum to both ports, it would put the door in the middle position, distributing partial air flow to the floor at all settings. I suppose a leaky vacuum motor diaphragm could cause this, as could a faulty heater control switch. If you set the controls to "floor," does the amount of floor airflow seem to increase?

If you'd like me to send you the vacuum and wiring diagram for the HVAC system, send me a private message with an e-mail address for you that can accept PDF attachments.

-Rod

The amount of air to the floor does increase when on floor only.

[shorod]

Based on that, and the vacuum diagram, I'd start by checking the floor-panel door vacuum motor. It appears that in floor mode, the motor should have full vacuum on both ports of the motor. In other modes, vacuum is only applied to one port.

You may also want to check operation of the door with the motor removed. Maybe the door is starting to seize and it requires vacuum on both ports to provide enough torque to fully move the door.

-Rod