Manually Operated Blend Door

[Dnyhart]

Cable Operated A/C Blend Door

my A/C blend door is cable operated and i was wondering if the blend doors that are cable operated are prone to break just as easy as the vacuum operated ones.
I have constant heat blowing out of dash and floor vents when i am driving no matter if the switch is set on cool and fan is off.

 

[Dnyhart]

come on people 81 views and no one wants to chime in? I guess im on my own on this.

 

[ChargerOnDavins]

I have no idea what a blend door is.

I can relate to your constant fan blowing at low speed, however. There was some small part you need to replace, I never did it. May be a resistor or something? Damn near every 1990's f150, f250, explorer, and ranger I ever owned had this problem, I just didn't care.

Also, don't try replacing the "unit" that controls the AC/heat and adjusts it.

It does nothing.

It's a coil or pack or something I can't remember a search on google for "blower motor always on" and ford will bring it up. Leave quotes where I put them for search, and then put +ford.

 

[TwoTrackMind]

Im not familiar with your particular setup (I have the electric operated blendoor and it broke over 5 years ago - I just added a cable operated heater hose control valve instead of ripping the whole dash out to fix it). But I have had alot of experience with older MoPar cable operated heaters. They always involved the cable becoming hard to slide, then developed a kink which allowed it to bend instead of operating the door. You might check for something like that.

The problem I had with my blend door was the end of the door shaft split (made similar to a socket). That allowed the actuator shaft (similar to the end of an extension) to spin inside and do nothing to move the door. If this is also your problem, and you choose to add the valve as I did, know too that you may need to "secure" your blend door open. Mine would sometimes close resulting in NO heat when you wanted it. A strategically placed screw in the bottom of the heater housing through the shaft fixed that.

Hope all this helps somehow...

 

[ChargerOnDavins]

Speak of the devil! My body guy messed up a canister vaccum line for my AC when removing my passenger side fender and now I am stuck on vent! Looks like I'll be researching this "blend door" too! LMFAO Karma!

 

[TwoTrackMind]

Back Up There a Minute....

My body guy messed up a canister vaccum line

The blend door controls the temperature only (mixes/blends more or less outside air with heated air). Other doors control where the air goes out of (dash vents, floor, defrost). All this control is done through the heater switches and knobs but they need a vacuum supply for power. The canister is a storage reservoir for vacuum coming from the engine.

Sounds like the vacuum supply (to the heater controls) was messed up. If this is the only problem, dont worry bout the blend door. Just repair the vacuum supply problem and everything else should start working.

 

[ChargerOnDavins]

The blend door controls the temperature only (mixes/blends more or less outside air with heated air). Other doors control where the air goes out of (dash vents, floor, defrost). All this control is done through the heater switches and knobs but they need a vacuum supply for power. The canister is a storage reservoir for vacuum coming from the engine.

Sounds like the vacuum supply (to the heater controls) was messed up. If this is the only problem, dont worry bout the blend door. Just repair the vacuum supply problem and everything else should start working.

Thank you! I will get on fixing it. Glad you could narrow it down for me.

 

[v8318cid]

Second generation Rangers used a cable-driven damper system to regulate air flow between the vents. I think they changed to the vacuum driven system in 95. If this is the case, the cable behind the control head has to be adjusted to fix the damper problem. I have a 92 that has issues with blowing air out of the floor ducts regardless of where the selector is placed. Unfortunately, I will need to dismantle the dash on mine to fix it since the cable is adjusted as much as it can be at the control head. By the by, if it is the cable-driven model, only the MAX A/C / OFF selection is controlled by vacuum. The other settings are purely cable driven. If you have a horizontal control setup rather than rotary controls, its cable. Look at the writing as well. If it spells out MAX A/C, PANEL, Panel-Floor, FLOOR, Floor-Def, DEFROST , then you have the cable driven system. The rotary controls used pictures for all positions except A/C, MAX A/C and OFF.

 

[Dnyhart]

Second generation Rangers used a cable-driven damper system to regulate air flow between the vents. I think they changed to the vacuum driven system in 95. If this is the case, the cable behind the control head has to be adjusted to fix the damper problem. I have a 92 that has issues with blowing air out of the floor ducts regardless of where the selector is placed. Unfortunately, I will need to dismantle the dash on mine to fix it since the cable is adjusted as much as it can be at the control head. By the by, if it is the cable-driven model, only the MAX A/C / OFF selection is controlled by vacuum. The other settings are purely cable driven. If you have a horizontal control setup rather than rotary controls, its cable. Look at the writing as well. If it spells out MAX A/C, PANEL, Panel-Floor, FLOOR, Floor-Def, DEFROST , then you have the cable driven system. The rotary controls used pictures for all positions except A/C, MAX A/C and OFF.

v8318cid thanks for the info about the cable adjustment, I think my post was sorta getting taken on a different path I will check that out and post my outcome.

 

[COPPERHEAD85]

I have the Vent only problem on my 81 F-100,its all vacuum and working with no leaks.
Both actuators work but it still go to floor or defrost.

 

[Dnyhart]

I guess i should feel lucky that my blend door is open towards heat and not cold so right now it is fine, temps are dropping and i work nightshift.

 

[tinglepepsi]

So you have to takeoff the whold dash to further adjust the cables. I did what the haynes manual said to adjust them but it still isnt working right. I also have air coming through all vents no matter if it is on or off, but only when moving. Any suggestions.

 

[v8318cid]

I'm not sure which configuration you have in the 94 so here's a stab in the dark. If its cable-driven, the only time you won't get any air flow at all when moving is if you set the controls to MAX A/C (or OFF if your truck is factory non-a/c). This closes the recirculation door and prevents air flow through the ducts when the fan is turned off. The cable adjustment would have to be made at the damper itself if adjusting the control head doesn't work. I'm fairly certain this would require removal of at least a few dash components if not the dash itself to access. Feel free to correct if I'm wrong about this. I never bothered with it myself and gave the truck away shortly afterwards. Unfortunately the recipient didn't heed my advice about making sure the A/C was turned off when the fan was off. He left it running and froze the evaporator, which subsequently ruptured...

 

[runtime]

Same Problem

I too have a 94 with what the same problem as the OP. It does have A/C, which is non functional. I've tweaked the cable adjustment with no improvement. So do suspect something broken with the blend door. Currently, I just bypassed the heater core until the temps once again fall.