hot air coming from vent

[shinta]

So my 91 ex is constantly leaking hot air from the vents. The blower works fine on all settings so I doubt thats the issue. Ive read several threads and I think it might be the door mechanism. So I pulled the dash apart looking for it and in true jared faahion couldn't find anything that looked like what was described. I did find a green box behind the glove box with ford on it and that was all. Its pretty close to the warm season here yuma so any help would be great.

What about the heater core valve bypass or something like that?

 

[FR-425]

Yep, you can just pull the two heater hoses of the heater control valve and connect them together.

Do not just plug them. The water pump needs to recirculate somewhere.

One of these and two hose clamps and your done!

Or you can replace the heater control valve as this is probably the issue anyhow. Hot water should not be in the heater core when the temp control is all the way to cold. Don't think your damper door is the problem.

If you move the selector from "max" a/c to "Panel" while you are moving, you will get air through the vents in the "Panel" position but not in "max" position. That will confirm that the damper door is working. (with the fan OFF)

 

[shinta]

Thanks for the reply. I went for a quick drive and moved the selector in all positions And the air is constantly flowing. So I guess that means the door. Do you know where I could pick one up and if there is a good thread to look into.

 

[FR-425]

The door is not a common failure on the first gens.

That is why there is no info on it.

The controls for the "mode" and "hot/cool" blend are done with cables.

If your remove the glove box you will be staring right at the cables.

On some models one cable runs all the way through the fire wall to the heater valve, and on others it pulls on a vacuum pot that then has a vacuum line that goes out through the fire wall to the heater valve.

The "mode" select cable is right at the plenum box just behind the glove box. (can't miss it)

So the problem is often just adjustment of the cables or the cable has broken or fallen off one end or the other.

 

[BKennedy]

I have one of these in the center console of the Explorer in case the POS plastic heater control bypass valve in the heater hose falls apart. I was changing out the hoses a few years ago and it just crumbled when I tried to remove it. Good insurance.

 

[Tbars4]

It is also common for the temp lever to break where the cable connects on the first gens, behind the radio..

 

[Maniak]

So my 91 ex is constantly leaking hot air from the vents. The blower works fine on all settings so I doubt thats the issue. Ive read several threads and I think it might be the door mechanism. So I pulled the dash apart looking for it and in true jared faahion couldn't find anything that looked like what was described. I did find a green box behind the glove box with ford on it and that was all. Its pretty close to the warm season here yuma so any help would be great.

What about the heater core valve bypass or something like that?

Even with the Heater control bypass valve on our '92 (I added it) we still get "some" heat through the vents. I've been trying to stop that off/on for years and so far I haven't found what is actually causing it. I "think" the blend door just isn't sealing as well as it could after all these years..

BUT, with that said.. You can add a heater control bypass valve AND tap into the MAX A/C vacuum line so when you are on Max A/C it will close the valve and keep the hot water out of the heater core. It does help get our A/C cooler..

Here is a thread that has pic's with it being added to a pre-94 explorer.

http://www.explorerforum.com/forums/showthread.php?t=142020&highlight=heater+mod

Edit: Here is the Heater Control Mod thread I found by looking at the HVAC section of the Useful Thread forum: http://www.explorerforum.com/forums/showthread.php?t=190431

~Mark

 

[shinta]

Whats up guys. Heres the latest. I put the bypass in and iam still getting flow, bit its more like outside air. Is there a door other than the blend door. Maybe that brings in outside air. Iam getting ready to track down any cablethat maybe broke or cam loose from the position lever.

 

[shinta]

Fixed it. Vacuum house below the pump in the hlove nox was cracked. Replaced the line works great. Thsnks for the help.