Heater/blower motor?
This check and fix is really easy, and quick, like maybe 20 minutes tops. Pull the blower motor from the engine compartment side of the firewall. Reach in with your hand and bend a few inches toward the center of the truck. Should be able to feel the coil for the AC. Remove any thing you can, by hand. Then using a shop vac, try removing even more. Be careful, the fins on the coil are easy to bend, and poking a hole in the coil will cause the system to lose the freon. Assuming you find some debris in the area, after cleaning as much as possible, you could use a garden hose on the coil. This will probably put water inside the cab, so not much water or just skip this.
If it helps increase the air flow, fine, if it doesn't help, at least you have not spent any money and very little time ruling out a plugged coil.
Good Luck Frank



