Blowing hot air instead of cool from outside

[brentharper]

Hi folks. Hope someone can give some good advice. I have a 96 Explorer. I would expect when I adjust the climate control knobs to give me outside air and no heat, then turn on the blower...I'd get the outside air coming through the vents. Not so...it's super heated. I'm guessing there must be a flapper in the ventilation box that's not moving and the air from outside is being drawn over the heater core. Interestingly enough, when I adjust the climate control knobs to give me air conditioning I do get some cool air coming in the vents but I assume the air conditioner has had to overcome the heated air that's passing over the heater core. Makes me think I might be very pleased with how cold the air conditioner would be if I correct the previously mentioned problem.

Grateful in advance for advice and links with pics on how I can troubleshoot and correct this problem.

 

[eXcali]

Hi folks. Hope someone can give some good advice. I have a 96 Explorer. I would expect when I adjust the climate control knobs to give me outside air and no heat, then turn on the blower...I'd get the outside air coming through the vents. Not so...it's super heated. I'm guessing there must be a flapper in the ventilation box that's not moving and the air from outside is being drawn over the heater core. Interestingly enough, when I adjust the climate control knobs to give me air conditioning I do get some cool air coming in the vents but I assume the air conditioner has had to overcome the heated air that's passing over the heater core. Makes me think I might be very pleased with how cold the air conditioner would be if I correct the previously mentioned problem.

Grateful in advance for advice and links with pics on how I can troubleshoot and correct this problem.

Check your blend door. Your fresh air intake is actually located inside your engine compartment, so if your engine is hot it will pull in hot air. Also try starting the truck and playing with the blend knob. With the system off you should hear the valves opening and closing allowing the flow of radiator fluid into the heating coils. On mine I will even hear a little gurgling sound as I switch it back and forth.

 

[TheJackal]

The heater core always has flow through it except when the right knob is set to "OFF" or "Max A/C"

If you get hot air when set to "Max A/C," then you either have a vacuum leak, a problem with the bypass valve, or an issue with the A/C refrigerant system.

 

[eXcali]

Your blend knob should control the flow of fluid into the heater core. My explorer atleast is not a computer controlled system that I am aware of. Turning the knob completely to the cold side will stop the flow.

 

[budwich]

sounds like the "standard blender door issue".... lots of posts. There is a post on the "surgery" to fix it which appears to work for most. Replacement is expensive and time consuming so people usually do some kind of kludge.

 

[evertsen1010]

where is surgery?

 

[dean1997sport]

http://www.explorerforum.com/forums/showthread.php?t=183742