2004 Ford Explorer 4x4, defrost problem

[keithwatson]

I get VERY LITTLE heat to the windshield in any defrost positions, When I first turn the system on I get a blast of hot air for about one second then a very little bit of heat to the defrost system. It would appear the defrost door is open until it gets vacuum. This is a three button manual system.

 

[Rick]

I moved your thread to our Stock 2002 - 2005 subforum.

 

[BrentW]

I have been asking the same thing. I bet your heater doesnt blow hard at your feet either does it? But when you turn it to Vent you get lots of air? Mine does the same exact thing and I have not been able to track down the issue and my thread on here didnt get me very far. If you do figure it out let me know because I have somewhat gave up on this issue. Sorry I am no help though.

 

[guy48065]

+1
Driving in the evening Sunday as temperatures fell from 35 to below freezing. Truck all warmed up and it starts misting outside. My windshield started icing up at the edges and slowly grew until I was hunched down in the seat to see out the lower 1/3 that was still clear. I have the electronic climate control and on Defrost, 75F, air coming out the top vent was just warm. It needs to be HOT.
It seems like everything is working as it should--dampers direct air to where told--but if this is the best it can do I'm not impressed.

 

[keithwatson]

Ford Explorer low heat on Defrost

I finally solved the problem, I spoke to the shop foreman at the Ford dealer and explained my symptoms. He said if you are getting air to the defroster then the doors are probably opening properly. He agreed that it was probably the selector switch which I replaced for $55.00 and it works great. This is the selector for air direction closest to the passenger seat (very easy to change). I did the following test, 1: remove the vacuum lines from the back of switch and with the vehicle motor running you should have vacuum on the black line (just hold your finger over the hole and you will feel a vacuum. 2: The second test I did was turn the selector to the off position, push the AC button, set your fan to high, slowly move through the air selector positions and you should feel an increase of air through the defroster. I hope this get you on track if so replace the selector with a NEW selector. The following web site gives a great explanation and diagrams for the heat and AC system for the Explorer. Good Luck
http://www.justanswer.com/ford/3814k-2003-ford-explorer-blows-vents-defrost-the-blend-door-ok.html

 

[guy48065]

Hmmm... well I suppose the digital climate control could have the exact same symptom, and cause.

 

[keithwatson]

Ford Explorer low heat on Defrost

An interesting situation, even with the new selector I found if I start with maximum heat and also on defrost you get a reduced air flow to the windshield. I am not sure but this may be normal. I have to start with reduced heat then increase to Max heat (the red zone). Hopefully someone with one that is working can confirm if this is normal

 

[BrentW]

I am hesitant to say that is my issue. My selector seems to change from position to position fine and you can watch the vacuum pots behind the dash move and to their thing as the knob is turned. It seems that when on Defrost and on floor both it gets hung like it didn't completely get to where it was going. The vents completely stop blowing though but right under the radio you can tell there is a lot of heat backing up there if you put your hand on the plastic. I am still of the opinion that something behind the dash is not moving completely into position. But next time I am at the salvage i will grab another selector just to see.

 

[keithwatson]

Explorer 4x4 defrost problem

Brent, what you are describing seems to confirm the selector as I believe it is not sending the correct signal, good luck

 

[guy48065]

I guess my thinking is different. My selector is different from yours, yet I have the same symptoms. I'm thinking it's a loose or cracked vac hose, leaky vac actuator, or something stuck in the diverter door.

That "justanswer" link above is awesome for describing what should be happening. I just don't know if much is different for trucks with the electronic controls. (I assume everything behind the rear of the control panel is identical)

 

[keithwatson]

Mine is working great just as it is described in the manual, lots of hot air (pardon the pun). I spoke again to the Ford dealer shop foreman and he said the selector switch was not an uncommon problem. All functions are directed through this selector. He caution against buying a used one as they may probably be faulty especially if it has not been used for some time. In Canada the slector price new is about $55.00 the price in the USA will be less. I found the following web site to have excellent information to explain the system.
http://www.justanswer.com/ford/3814k-2003-ford-explorer-blows-vents-defrost-the-blend-door-ok.html

 

[guy48065]

I think I may have 2 problems. The valve in the coolant hose that lets hot water flow through the core is closed and not getting vacuum. I'm trying to find the vacuum switch in that line but not having much luck.
Also my blend door might be stuck. If I force the heater valve open I still don't get hot air out the vents at any setting. There is no noise from the blend door motor but I haven't had a chance to find the problem. Too cold out to work.

 

[keithwatson]

2004 Ford Explorer defrost problem

If you remove the vacuum cables from the bottom of the selector switch with the engine running you should have vacuum at the black hose. You may want to fit a a line to each hose and gently suck on them to clear any blockage. Remember a lot of the problems come from the signal sent from the selector switch, you may want to try another one that you know is good. I am currently in -30c weather and so far mine is text book working. Good luck

 

[guy48065]

All my diverter vac actuators work normally--the only vac line with a problem is the heater valve. My diagram shows the vacuum switch in that line, one in/one out, so that's my primary suspect. Too cold to actually work on it right now so I'm trying to find as much info as I can to prepare.

The electric motor that operates the blend door looks to be a PITA to replace so it definitely needs to wait. Good thing I can let the truck sit.

 

[keithwatson]

You may want to also check the electrical wiring circuit as the selector switch also send signals to the motors to change the vacuum settings. You may also try and push the AC button and then try your heat selection. This gave momentary heat when I was trying to fix mine before I replaced the selector switch.

 

[guy48065]

You may want to also check the electrical wiring circuit as the selector switch also send signals to the motors to change the vacuum settings. You may also try and push the AC button and then try your heat selection. This gave momentary heat when I was trying to fix mine before I replaced the selector switch.

Can you explain what you mean by electrical signals to motors? I thought vacuum did all the grunt work, except for the blend door.

 

[keithwatson]

defrost problem

At the bottom of the selector switch is 4 or 5 electrical wires which I assume send different current for the functions. I did not research their functions but assume each have a different control.

 

[guy48065]

Are you talking about the electronic climate control panel? I think those would be for power, ground, dash lights and maybe the output to the blend door motor.

 

[keithwatson]

I am not sure as I said I did not research the wires, they are the ones on the bottom of the selector switch below the vacuum hoses