I had already determined that the blend air door was broken in this 1999 Ford F150. There are some hacked up ways of changing this door and if that is what you are looking for this article is not for you. Although there are a lot of steps involved in replacing the broken blend air door, it only takes two to three hours to complete. The same procedure can be used to replace the heater core and the evaporator core. I will be breaking this down into smaller sections so that it will not seem so daunting of a task. Both for you to do and for me to document.
This repair applies to:
1997 Ford F150 & F250 Pickups
1998 Ford Expedition, F150, F250 & Lincoln Navigator
1999 Ford Expedition, F150, F250 & Lincoln Navigator
2000 Ford Expedition, F150, F250 & Lincoln Navigator
2001 Ford Expedition, F150, F250 & Lincoln Navigator
2002 Ford Expedition, F150, F250, Lincoln Navigator & Blackwood
2003 Ford F150, F250 & Lincoln Blackwood Pickups
2004 Ford F150 & F250 Pickups
There will be differences in higher trim models. In particular models with a floor mounted center console. I have done this repair on a Ford Expedition (with a center console) in the past and I do not remember having to remove the center console. In fact I think it was slightly easier because the console provided a good resting point for the dash assembly.
The passenger side pull handle has to be removed. There are two rubber covers that have to be removed. They will pry out easily with a pocket screw driver. Note that on the underside there are offset notches that allow them to only be installed in one direction.
The screw heads are 7 mm hexes.
There are two more covers that are made of a harder plastic that are closer to the windshield. I had to switch to a ratchet and socket combination to remove those two screws. Also keep these four screws separate from the rest as they have different head designs and threads.
With all four screws removed the handle will slide out of the mounting holes.
Now the “A” pillar trim panel can be removed. Grab it at the top edge and pull it away from the metal pillar.
Once the upper edges are loose it will pull up and off of the hook on the lower inside edge.
Now the rocker trim panel needs to be removed. It can be lifted from the front or the rear edge.
Now the kick panel trim cover can be removed by pulling it towards the rear of the vehicle.
All of the harness connectors have to be disconnected at the junction panel. The harness also needs to be pulled from the body panel as shown below.
One ground screw needs to be removed that holds the harness ground wires to the body.
Now the upper dash trim panel needs the insert removed. It is held in place by multiple spring clips. I had to work the panel from both ends to get it free. This one had a sensor to the left of my hand that had to have the harness disconnected from it.
Now, the air bag mounting screws have to be removed. You really should follow the factory instructions for disabling the airbag or SRS system before removing the airbag
The glove box door has to be opened to access the lower airbag mounting screws. There is a latch at either side that has to be pushed over so that the glove box door will open fully.
The air bag is attached with three 8 mm headed bolts. One bolt on the lower left side.
One at the top center position.
I took this picture through the windshield to give a better perspective on it’s location.
The last bolt is on the lower right side of the airbag as shown below.
The airbag will slide out far enough to disconnect the wiring from the assembly. Again follow the manufacturer’s instructions for handling the airbag. The airbags are relatively safe to work around but you always need to keep the fact that they are an explosive device in the back of your mind. You can be hurt or killed if they are improperly handled.
In the process of determining that the door is broken you would have already taken this panel off. There are a total of three push pin retainers that have to be pulled out: Two on the driver’s side and one on the passenger side. The things to check in diagnosing this problem are: The coolant level is not low, Both heater hoses should warm up evenly from a cold start up to fully warmed and The actuator shaft should rotate in a 90 degree arc as the switch is turned from full cold to full hot. If all of these are okay the door is broken. Sometimes you can see that the door shaft is split where the actuator shaft enters it.
With the cover removed the right lower dash support bracket needs to be removed. One screw at the top.
One nut on the bottom. With both removed the bracket will lift up and off of the stud in the floor.
While you are here you might as well remove the nut for the left lower support bracket.