Vent still blows hot when set to cold

[cold_steel]

Hey, I'm having a problem where my heater blows hot air full blast no matter if it is set to hot or cold. I'm not talking about fan motor speed, that works fine, I'm talking about temperature. If I turn Max A/C on it overcomes the heat and blows cold, and if the A/C is left on long enough it will still blow cold when set to vent, but if you turn the temp control to hot and then back to cold (still set to vent) it will stay hot. Any ideas? If a vacuum line controls this, where can I find it?

 

[97BlackBetty]

Hey i got the same problem in my 97'. Whats causing it is that the gate that controls the hot/cold air flow in the heater core tends to get gunked up after a while. I've just lived with it cause up in the north i like to have the hot air. Ford tells me that the only remedy for the problem is to replace the heater core, which as of two years ago they wanted $1000!
Justin

 

[cold_steel]

Wow that doesn't sound good... anyone else have this problem/know of any alternative solutions?

 

[1987 DANGER RANGER]

I dont belive it would be the heater core which is causing you prolbems and if so they are only around $35 to replace. I would guess it is the blend door, which goes no way for hot and the other with cold. A litter bit of everything can get around the post which it rotates on. You could pull the dash and clean the blend door but I would guess that would be pretty tuff.

 

[metalmacguyver]

actually i just replaced my blend door from the engine compartment side of everything. i used a bolt nut and sleeve that i could turn with a wrench to force the air plenum to spread apart so that i could pop the in and out.

i found that the temp selector had been forced past its stops. the control is a variable resistor. it tells the servo what position to be in. by forcing it past the stops it told the servo to go to far so the part where it connects to the door broke.

 

[cold_steel]

So it is sort of accessable without taking the dash apart? Sounds like that might be the route to take... did you have any kind of diagram or whatnot to use?

 

[metalmacguyver]

i did take lots of pictures. i will put them on my cardomain page in my signature. i had a big advantage in that the previous owner purchased the new air plenum that the blend door is in so i could see the entire thing that i was working on with out removing the origional plenum.

before we get any further into this, what model year exactly is your truck. my 96 ranger had a mechanical temp selector knob with a cable that went to the blend door. my 97 that i just fixed has an electrical set up like i described before.

ill post those pics on cardomain.com shortly.

 

[cold_steel]

its a '97 ranger single cab stepside, 2.3L

 

[cold_steel]

found this:
http://www.blenddoorfix.netfirms.com/
viable fix or is it BS?

 

[metalmacguyver]

thats fawking genius! i should have thought of that.


it is a very viable fix. good luck with it. much easier than my way.


MODS: this web site should be sticked in the heat and AC section!
http://www.blenddoorfix.netfirms.com/

 

[thebison]

wow you are a genius, ive been having the same problem with my 97 b4000, ive takin all that apart but never thought of an idea to fix it, thanks for the help

 

[metalmacguyver]

it is important to remember the cause of this problem though. that electric servo had the power to break the door before and it will have the power to do it again. either replace the dial in the control panel or be very careful about how far you turn it in the future.

 

[metalmacguyver]

wow you are a genius, ive been having the same problem with my 97 b4000, ive takin all that apart but never thought of an idea to fix it, thanks for the help

thank the guy that came up with the idea!