I have determined the control that sends air to dash vents or floor or defroster and all the combinations in-between works. The diaphragm is moving the arm. The blend air door moves when the diaphragm rod is pushed into the diaphragm.

The shop manual references a "blend door actuator", page 2754, which I think may be my problem since I get cold air or hot air, with no in-between. It's not clear exactly where it is, but I see something resembling the drawing at the bottom of the dash assembly on the passenger side above the heater outlet. Can it be removed where it is, or do I need to remove the HVAC housing as the manual says? Don't want to have remove what I don't have to. Seems like every time I look, another piece of internal plastic shatters and falls to the floor.

Am I chasing the right part? Any advice is appreciated.

Joe Truckster

 

If your truck is 2000 or newer, then yeah, the funny little box on the bottom of the hvac box is the blend door actuator. There is a plastic couple between the actuator, and the axle for the blend door, that cracks, and allows the door to flop around. HeaterTreater.com has the fix for that. (an aluminum coupler.) You don't have to pull the heater box to remove the actuator, but, there is one screw that is rather difficult to get to. Some folks cut the carpet a bit to make it easier.

 

I have checked out HeaterTreater, but didn't realize (didn't know enough) that that is what HT is for. I'll pull it out and take a look and order one.

Watched LMC's video on dash top replacement, so once I get blend door thing fixed, dash repair will be next. Picked up various pieces of thin steel / sheetmetal to make brackets to hold HVAC controls in place.

Thanks for information.