need some heater advice

[jebadiah04]

85 f150 factory ac

a few years back I was driving and all of a sudden I got a huge cloud of white smoke from the heater. I pulled over. No smoke under the hood. I fired the truck back up. A few minutes later the same damn thing. Turns out when I switched from defrost to floor something died. Now I have air going to all 3 places all the time. The funny part is I can hear the mixer door opening and closing when I move the lever from floor to defrost or back.

Any ideas? Fan works fine I pulled it out and looked in there didn't see anything wierd. Can't see much. Where to check?

 

[DNFXDLI]

Did it smell like antifreeze or electrical?

 

[Fellro]

Also look for the stream running down the firewall under the heater area. I have had the core go out but just mostly dump it on the floor.

 

[m78]

I'm not familiar with the type of controls on that truck. Are they electric motors
on the mixer door or vacuum ?

 

[fatherdoug]

I believe they are vacuum actuated.

 

[Fellro]

They are vacuum. There is no puff of smoke possible from the actuators. It likely was when the core blew out.

 

[jebadiah04]

The core is fine. This was 8 years ago that it happened. Lol I just never fixed it. It's never leaked.

The smoke was 100% Electrical but I don't know of any electronics in it except the fan.

is it like a chevy where the resistors for the fan are mounted in the heater? Is it possible that they lit a leaf or something on fire and melted the mixer door or something?

It did the burning right after I switched it from defrost, where it had been for a while. I start Electrical smoke. But everything still works on the truck except the mixer.

 

[Fellro]

The resistors are in the air stream, so it is likely that something got against it. The blend doors do have a gasket, and if I recall, one has a foam covering on it.

 

[jebadiah04]

How do I get to the door. I don't think it's the hot/cold door it's got to be the defrost/bi level/floor door

 

[Fellro]

That is the ductwork under the dash. The one under the hood is for hot/cold.

 

[jebadiah04]

Ok so I yanked the glove box out. Heater core cover off. I found the problem. The blend door that flips it from mid to fl/def. Is goofy. It's not flapping but it is flopping all around like the hung is gone. Of coarse I can see in there only feel but I can't feel anything that resembles a hinge. I also can't figure out how to get to it. I have the dash pad off...not much luck so far.

 

[jebadiah04]

It is still hooked into the actuator and the actuator just makes it slide like a grocery store door. Lol.

 

[Twiceblown351]

The only way to get inside the box to fix the door that i know of it to take the heater box out. and the only way to get the heater box out is to take the hole dash out of the truck.

If it remember the door is stapled to he rod that the cable moves. I have seen it happen before to all kinds of cars and truck. but its not something you see very ofen.

 

[jebadiah04]

Just got it back together. What a PAIN!!!

had to take the dash pad off, glove box out, remove the mounting bracket on the right. Loosen all the other ones up, radio out. Gauge bezel off. Heater core cover off. Then i could pull the right side of the vent up just enough to remove the broken flapper. Had to grund off the rivets remove a couple of screws. Mine doesn't have a hinge or a pin. It uses a piece of plastic that it bends back and forth until if finally falls apart. I took a couple of pictures I will upload once i get the radio back in and test things.

Fixed a couple things while i was in there. Made a run at the clock..but it didn't fix much and replaced the headlight switch which was getting a Lil funky. Not super happy about all the hairline cracks in various parts of my dash i found. Might need to put something on it to soften the plastic up a bit.

 

[jebadiah04]

Redneck dome light

 

[jebadiah04]

Can't post the pic I took of the flapper since it's apparently too big. I used same camera on the redneck dome light so I dunno what's up. Anyways I gorilla taped it back together and it works awesome. Interestingly enough I learned that all that flapper does is swap from vent to not vent. There's another one further down the line that swap from floor to def. So there is 3 places air direction can go haywire in these things. I think I have now officially takes every bolt out of an 80-86 and put it back in.

seriously.

and there are a damn lot of them.