Section 12-02: Heating and Defrosting
1996 F-150, F-250, F-350, F-Super Duty and Bronco, F-Super Duty Motorhome Chassis Workshop Manual
REMOVAL AND INSTALLATION

Vacuum Control Motors

 

Air Inlet Duct Door

Removal

  1. Disconnect the connector and remove the blower motor (18527).

  1. If only the vacuum control motor (18A318) is to be removed, disconnect the two screws that attach the motor to the upper surface of the outside door duct.

  1. Pry the vacuum control motor and arm assembly upward at the arm end to free it from its mounting peg. A retaining flange that is an integral part of the crank, peg, and flange component may partially obstruct the arm in its upward movement along the peg. If this retaining flange should break off when forcing the arm upward, a 3/16-inch spring nut (Part No. 383358-S) must be used to retain the arm when the same or replacement vacuum control motor is installed. The following illustration shows removal in View A and the area in which retainer flange breakage might occur in the main view.



    Outside Air/Recirculation Air Door Vacuum Control Motor Installation





    ItemPart NumberDescription
    139085-S2Screw (2 Req'd)
    2—Motor Arm (Part of 18A318)
    3—Peg (Part of Cam)
    4—Retainer (Part of Cam)
    5—Electrical Wiring Harness
    (Part of 14401)
    618A318Vacuum Control Motor
    7383358-SSpring Nut

  1. Look through opening in the heater assembly and use a screwdriver to depress the snap-on door crank, while pulling up on the door shaft to release the crank from the door.

  1. Remove the door through the opening.

Installation

  1. Insert the door through the opening. Seat the bottom door pivot first, then swing top door pivot into place.

  1. Hold door in full outside air position (swing to full-in board position) and snap in crank.

  1. Align the hole in the arm with the peg in the door crank.

  1. NOTE: If the flange has been broken off, install the spring nut as shown in the Outside Air/Recirculation Air Door Vacuum Control Motor Installation illustration.

    Slide the arm downward over the peg and along the inner surface of the retaining flange where the arm seats below the base of the flange surface.

  1. Install the blower motor in housing and connect electrical harness.

 

Floor Duct Door

Removal

  1. Remove the heater outlet floor duct (18C433). Refer to Outlet Floor Duct in the Removal and Installation portion of this section.

  1. Disconnect the two vacuum hoses from the vacuum control motor.

  1. Remove the two screws which secure the vacuum control motor and bracket assembly to the heater air plenum chamber (18471).

  1. Using a small screwdriver, depress the tang on the side of the door operating lever and pull the arm out of the lever.

Installation

  1. Follow removal procedures in reverse order.

  1. Make sure locking tangs are securely engaged when motor arm is slid into door lever.

 

Air Damper Door

Removal

  1. Remove the vacuum hose from the vacuum control motors.

  1. Remove the two screws that attach the vacuum control motor to the heater air plenum chamber.

  1. Rotate the assembly so that the motor arm slides off of the crank pin. Pull the vacuum control motor and bracket assembly off the crank arm.

Installation

  1. Follow removal procedures in reverse order, engaging tee-shaped end of door crank arm into slot in vacuum control motor and bracket assembly.

  1. Rotate assembly into proper position.