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My blower motor only blows hot air... and I mean HOT! I'm thinking it could be the blend door actuator but I'm not sure. I still need to hook up the AC for the summer but I just need some airflow when I'm stuck at stoplights.
AC not working it will blow hotish air.
The heater core has hot water flowing thru it all the time.
The HVAC box is partly in the hot engine bay picking up heat.
The temp door is moved by cable behind the glove box IIRC so you can check that it is moving as it should.
The " blend door" that breaks is for defrost / vent / floor and the hinge breaks so it will not move.
Vacuum makes this move.
BTW if I dont have mine on AC it blows hot air and even more so when stop as the hot air under hood dose not get blown out.
Dave ----
If you want to do a test, crimp off one of the heater core hoses under the hood to block the coolant flow to the heater core. See if it's a little cooler. Most of them do leak a little hot air. It can hurt your A/C output also if you ever get that working. There is a modification you can do and install a water valve off a little ranger pickup to block the waterflow to the heater when you get your A/C working.
The heater core sits in the duct, downstream of the heater fan and AC evaporator. With the engine warm, the heater core is always hot. A cable operated door (Ford calls it the temperature blend door) routes air through or around the heater core, depending on the position of the upper lever on the control panel.
With the key off, move the temperature lever back and forth full travel. You should feel some resistance as the door moves, and hear a thump from inside the plenum as the door reaches full travel in each direction. If not, the cable may need some attention. This view, above the passenger's feet with the glovebox removed, shows the cable secured by the plastic orange clamp towards the upper right. Note the cover has been removed from the heater core:
The lever for the door (at the end of the cable) is in the shadows to the left of the clamp. I think you can snake your hand up there without removing the heater core cover, but am not positive. If you can hear the thump at each end of travel, there's no need to investigate the cable.
If the door is moving properly, the seals may have failed. I've never had mine apart, but think the seal is made of foam which may have disintegrated. From my understanding, it's a big undertaking to replace the seal and it may not be necessary if you add a coolant shutoff valve.
See this thread for details of the coolant shutoff valve and how to tie it in to operate automatically:
I highly recommend adding the coolant shutoff valve. It works very well and makes a big difference. I'd guess on any truck of this vintage, the seals on the temperature blend door have failed. Adding the valve is way easier than tearing the dash apart.
Make sure the seal between the hood and firewall is in good condition. If not, hot air from under the hood will reach the HVAC inlet at the base of the windshield. This will be more noticeable at lower speeds.
