Truck hvac issue

[jstubbs]

Howdy all,

Got a conundrum for any internet mechanics out there.

2013 F450. There is little to no air coming out of the vents. Blower motor is audibly working and sounds exactly as it should. The sound of the blower motor changes with adjusting the fan speed as you'd expect. No unusual vibrations or noises at all. The air blows OK when first started after sitting for awhile (but never at more than half power air when set at full blast) and slowly tapers off within a few minutes to nothing. The fan doesn't sound any different as that happens.

I've dealt with bad blower motors (but usually either can hear it running like crap or don't hear it at all), bad blower motor resistors (usually then fan speed doesn't change) and vacuum blend door issues (usually blows out at least one vent). Haven't had much time to mess with it and if anyone's dealt with something similar that could save me a ton of time.

Thanks!

[Bergerboy]

Pull the cabin air filter first to see if that makes a difference.

[Ken07AOVette]

It's likely the blender motor under and behind the glove box

[schleprock]

No cabin air filters in the f250 to f550 2011-2016 series.

[flange]

Evap maybe freezing up maybe ?
Low charge can cause this

[EZM]

Sound crazy - but make sure your coolant is topped up - my f-150 did the same thing and I topped up the coolant as someone here on the forum suggested and everything went back to normal and it was back to blowing cold.

it may not be the case in your situation but worth a look anyways ... fast, cheap and easy.

[BlackHeart]

Sounds like the fan propeller unit is spinning on the shaft of the blower motor. When cool (and after the plastic has resolidified) the blades will turn, but once it heats up again there is no grip on the shaft and the plastic has softened due to friction....hence the loss of blowing.