Heat keeps blowing out of the defroster and the floor vents

[4x4TILL_I_DIE]

I keep having heat blowing out of the defrost and floor vents even when the control is set to off. It will stop only if i turn defrost ON and set it cool or if I turn the A/C on thats it. I have resorted to stuffing a glove into the floor vent and diving with the windows down but it gets HOT lol. Please help me figure out how to fix this.

 

[Bronco638]

Sounds like a Blend Door issue. It's a common malady with Explorers and Rangers, apparently. In an Explorer, it's a pretty good project. Not hard, just lots of things to do. I suspect the job is similar, for a Ranger.

 

[4x4TILL_I_DIE]

Anything to do with the heater core. The door in that was broke when I got the truck and I had that fixed at a shop cause that involved taking the whole dash out. They said that the door was not replaceable had to get a whole new unit.

 

[rtg143]

If that happened right after their work, I'd talk to them about it. A vacuum leak can also cause that.

 

[4x4TILL_I_DIE]

No that was several years ago maybe 4 or so

 

[4x4TILL_I_DIE]

Any idea where to look for info on how to fix a blend door issue or a vacuum leak that would cause the problem?

 

[rtg143]

Here's the diagram. The blend door controls the temperature and vacuum controls the air direction.

 

[stedman]

I've got the same problem with my '96 Ranger XLT. Just found a neat fix this morning, at $119 and 2 hours of work. Got to www.heatertreater.net.

thought it was pretty cool, couple videos showin' how to do the job. I'm going to verify that it is the blender door before I go this route. I'm going to glue the panel back on that you'll have to remove to gain access to the blender door.

 

[rtg143]

Keep us posted.

 

[Chris_North]

Have you tried setting the temperature control to cool and leaving it like that? If that doesn't work your primary problem is likely the blend door. As mentioned it is a common problem with explorers and rangers. What's unusual is that you said you can make it stop by turning the defrost on and setting the AC? Do you have any other problems like always getting heat no matter what the temp setting?

The heater treater fix works great to replace a broken blend door, but if that's not the problem it obviously won't help. I had a broken blend door issue myself which gave me a similar issue, but until I bought the HT blend door I just cut a hole in the heater plenum (as if to install the new door) but just taped the old blend door to fully block the heater core in the summer and fully block the evaporator/outside air intake side during the winter.

At least on my 98, Max A/C will close off the flow of hot coolant to the heater core and prevent it from getting hot, thus preventing any heat from getting to the cab.

 

[rtg143]

Does the air flow only flow through the defrost and floor?

 

[4x4TILL_I_DIE]

Ok I have figured out that the blend door actuator is moving I turn on the key, put my hand on top of it and turn it from hot to cold and I can feel it moving.
The heat will only come out the floor and the defrost. If I turn on the ac it works just fine at what I set it at likewise with the defrost.

Do I have another problem? I'm stumped

 

[Dale_K]

My Ranger is newer so this might not be right for your truck but I think there is a valve in the cooling system that shuts off the hot water flow through the heater core when the truck is in the A/C mode, either recirculation mode or regular A/C. If your truck has the same valve and it's gone bad, that could explain why the heat comes out when you don't want it. You could either fix the valve or replace it with a manual valve that you shut off by hand each summer.

I'm not a expert and my truck is different so I could be wrong.

 

[4x4TILL_I_DIE]

Yup heater valve I have it and it was bad replaced it and now I'm wondering if the new one was junk.

 

[4x4TILL_I_DIE]

Still coming out of the floor