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Ford F-Series Climate Control



  • Can i replace my manual climate contol head unit with a full automatic climate contol head unit from a different vehicle??
  • I have a 1900 F-150, no matter what output I choose (A/C, Heat, Vent, etc.) the air flow is only through the defroster vents. Could there be a vacumn issue with the diverter? A bad control unit? Please advise.

  • I have a question about the temperature selector on a 1997 Ford F-150. How do you test the switch? We have taken it out found 3 prongs labeled 1, 2, & 3. What do these mean and are you able to test it to see if it is bad?
  • I just replaced the heater switch on '06 F250 because it was only putting out heat when on high. Now my new switch is doing the same thing. Anyone have an idea what might be causing this. Fuses # 22 & 28 are not blown.
  • I have a 2001 F-150, once the heat gets up to the normal range I turn the heater control switch from off to floor or vent/floor. For about 30 seconds I get warm air and then the airs cools quickly. I can turn the controls off for about five minutes then back on and it works fine for another 30 seconds. I have noticed that both heater hoses seem to be about the same temperature so I don't think the heater core is totally stopped up. I can tell a sight difference in the air coming out of the vents if I change the heater control for hot to cold and back.
  • I have the same probelm. I have a 99 F-150 and it blows cold sometimes and hot sometimes. The vent selector works just fine, if I want defrost I get it, if I want floor or panel I get it. The problem is with temp control. I replaced the potentiometer for the temp control and no change. The probelm has to be with the "mixing valve" (at least that's what I'm calling it) that regulates the desired temp selected on the climate controller. Does anyone know where this valve is located or how to replace it. Or does anyone have any other ideas? Thanks
  • supercrewzersupercrewzer Posts: 1
    edited April 2010
    2001 Supercrew, 82 k

    I've notice a dripping under the truck after I've driven it. Looks like the dripping you see from A/C condensate, but this has been occurring during the winter. It is clear, and odorless, colorless and tasteless. Today, about 70 degrees outside, driving with window open, I had the temp setting to cool, A/C off, and the vent was switched to Panel/Floor. I expected the air coming from the vents to be about the same as the outside air. However I found it to be quite cold, and obviously the A/C was running. Switching the vent to "Floor" or "Defrost/Floor" I could hear the A/C compressor turn off (click from under the hood). By trying the different vent control settings, it appears that the A/C compressor is turning on when I switch the vent control to Panel/Floor, or of course if I switch the A/C on deliberately. This seems odd since the A/C is normally not on unless the "A/C" setting is selected. Also, you can't select "A/C" (on the left side of the control dial) and "Panel/Floor" at the same time (on the right side of the dial) since they are both control by the same knob. Since I usually run the Panel/Floor vent setting when I have the heater on during the winter, it seems this is why I was seeing dripping under the truck.

    Is this a rotary control switch problem?
    Is the A/C supposed to turn on when Panel/Floor is selected (and perhaps I didn't notice it before)? Thanks.
  • joe289joe289 Posts: 1
    dryfly you are a genius. I looked on the right side and the vacuum box ,directly behind the battery on my 2001 F-250 super duty, had a hole worn or burned in the top and it was leaking air. I temporarily plugged it and it fixed the selector problems. Can't see anything that wore the hole it it but with a little RTV I expect to be back in business soon. Thanks for the idea.
  • I have a similar problem. I also have a 99 f150 and the ac works and the heat works. The vents all work when I change from vent to defrost to floor. My problem is when I start my truck all I get is cold air even when it is heated up. This is with temp set on cold or hot. When I drive at highway speed, say 55 or more then stop at a stop sign or light it starts blowing hot. Driving through town it will keep blowing cold so long as I don't get up to highway speed. So is this a vacuum problem or temp control problem or blend door problem? Could the quick stop and start at highway speed cause the blend door to change if it were broken? Thanks for any feedback.
  • 1989 F350, replaced AC compressor, drier and orfice tube, put oil in the new compressor, and charged the system, it never really got cold and then a line burst.
    Any ideas what could cause this?
  • Deforst is the default mode - gov't mandate. I suspect you have a vacuum leak where the vacuum harness connects to the back of the control head. Try to see if you press it tight, if it works ok. See if you can use tie straps to hold it tight to the control head.
    Last resort - cut one at a time off the harness and connect each one to the control head with a 1/8" (I think) piece of clear hose.

  • Did you ever get this fixed? I just got in my truck yesterday and the fan motor was stuck on high. when I turn it off it starts blowing on defrost
  • Had to look under the hood today and found a vacuum line unplugged. It attached to the switch right behind the engine oil fill. Question is I am seeing corrosion similar to that on a battery terminal on the same switch dripping on the engine. Can anyone explain this? Heater and AC work great. also to all that have a problem with your heaters not blowing warm air CHECK THE COOLANT LEVEL. I had that problem just need to top it off.
  • jay174jay174 Posts: 1
    edited November 2010
    Yesterday morning I started my truck and was suprised to see that every indicator was lit up on my Climate Control. Every thing that could light up on the display was lit up and I when I attempted to use any of the climate control buttons there were all unresponsive. Any advice or if any one has experienced this problem and help you maybe able to provide would be greatly appreciated. Thank you.
  • I have a 2001 F-150, once the heat gets up to the normal range I turn the heater control switch from off to vent/floor. After about 20 seconds I get warm air and then the airs cools down quickly. I can turn the controls off for a few minutes then back on and it works fine for another 30 seconds. I believe its blowing the heat through the vents from the engine heating up. I have noticed since having the truck that the radiator fluid levels are always the same & I have had this truck for 9 months now. I checked all the mini fuses and only one was blown, it was the fuse for my trailer hook up lights. Can someone please help me with this problem, I have two lil girls riding to school each morning wrapped in a electric blanket... Please and Thanks
  • gmj0311gmj0311 Posts: 1
  • jgorskijgorski Posts: 1
    I have the mechanical linkage control (two cables) the door works fine but it will not close all the way. I can push it closed with my hand but upon cycling the switch again it remains partially open. I have removed the control at the dash and at the blend door. I can see nothing wrong with it and see no way to adjust it.
    Please help, it's to hot to drive this way.
  • wilskiwilski Posts: 1
    edited June 2011
    I start truck, turn air conditioning on and it blows cold. When I accellerate it blows warm. The compressor lines are cold all the time. Is there a vacuum motor controlled flap?
  • Blend door could be broken at the hinge where it fits in the blend motor. That depends on year of your truck I suppose, though. Look up
  • I have the same problem ... did you ever get it fixed ?


  • I just bought a 2006 F-150 King Ranch. My problem is that I can't control the interior temp., in particular the heat. Since I live in Alaska the air conditioning isn't used. No matter if I use the auto or manual selector, no matter the temp. setting I use the interior temp. seems to have no upper limit - it just gets hotter and hotter. I can stop the heat by selecting an interior temp of 60 deg. which then cools the cab to an uncomfortable level. Any ideas on how to fix this? Is there an internal thermostat that I can replace?
    Thanks -
  • I have the same exact problem as #68.. its gettin cold out and I need my heat! Heat for only 30 seconds just don't cut it..blend door if fine, so is radiator, accuator,heater core, blower motor... what the heck???? What is wrong with my truck??
  • jonn58jonn58 Posts: 1
    my climate control lights wont work but ever thing else does
  • wwestwwest Posts: 10,706
    [quote name= timestamp='1349462036' post='5070'] Not this odor. It's more like a ether smell [/quote]

    For many years, more than 20, manufacturers have been experimenting with various methods for retarding or even eliminating the growth of the microbe colonies that result in the mould and mildew odor emanating for automotive A/C systems.

    Some Lexus models currently incorporate a UV light source inside the A/C plenum. Another approach seems to be to lightly coat the evaporator cooling vanes with a fungicide. This latter seems to encounter 2 problems, the fungicide washes away within just a few weeks, or it is found that the fungicide chosen is adverse to human health.

    It turned out that the evaporator in our new '92 LS400 was first coated with a thin porous nylon film and then dipped in the chosen fungicide to fill those pores. The problem came to be that once the fungicide (shortly) washed out of those pores the evaporator became a huge SPONGE for holding condensate until the exacting conditions arose for sudden, FULL, and virtually INSTANT evaporation.


    The (cool/COLD) interior of the windshield suddenly fogs over to the point that all forward vision is lost. THEN you discover that Lexus relies SOLELY on the A/C for airflow dehumidification and interior windshield defogging in defrost/defog/demist mode...BUT...the A/C is automatically disabled (with NO indication to the driver of same) when the OAT declines to/below freezing.

    Even were the A/C still enabled it's functionality for airflow dehumidification is significantly degraded as the OAT declines closer and closer to ~33F. Lexus at first admitted, full disclosure of this, but then subsequently discovered that no MSDS had been filed with the proper US agencies and began denying that a coating was/had been used.

    Since ~'94 my LS400, and now my '01 RX300, and '01 Porsche C4 are all modified such that I can easily and indefinitely disable, FULLY disable, the A/C during the periods wherein it's only use would be for airflow dehumidification. The climate control in my '92 LS400 has an internal DIY electronic control modification that will automatically turn the HEAT to maximum the instant I switch into defrost/defog/demist mode, the blower speed rises to maximum accordingly. In my RX300 I always remember to quickly twist the temperature setpoint knob fully clockwise just prior to switching the system into defrost/defog/demist airflow routing mode. Luckily Porsche has not yet adopted the NipponDenso, Denso US, climate control design IDIOCY so it still automatically goes into HEATING mode whenever the windshield defogging function is activated.

    During the period between purchasing the new '92 LS400 and coming up with the DIY modification, ~94, I alleviated the propensity for the sudden fogging of the windshield, and to a lesser extent the odor problem, via religiously lowering the windows slightly in the garage each and every night.

    So, why is this important to you, an F150 owner...

    ALL Asian models use, have always used, the horribly flawed NipponDenso climate control operation model, and with the establishment of Denso US (via merger/acquisition?) many US models are now subject to this problem.

    How to tell...??!!

    Allow your automatic climate control to fully stabilize at your temperature setpoint comfort level. At this point many [most?] of "these" systems will automatically switch into cooling mode, face and upper body airflow routing. Once the system has stabilized then switch the system to defrost/defog/demist airflow routing, if you then do not get a significant level of HEATED airflow then your system is most likely modeled after the IDIOT Denso US design.

    In about 2005 I stumbled across the fact that Lexus was secretly addressing the problems, my '01 RX300 had dealer set options that would allow me to turn off the A/C function indefinitely by simply turning it off manually one time. The system would then not activate the A/C compressor clutch, not even in defrost/defog/demist mode, until I switched it on, enabled it, again.

    RX models newer than my '01 have additional dealer set options that could be used to prevent the automatic switch into cooling mode on the darkest, blackest COLD wintertime night. Plus 1 or 2 other options, differing actions with defrost/defog/demist mode with the OAT below 33F, for instance.

    So here we are well into 2012 and it may well be that many other models, US especially, have adopted a few of these dealer set options in order to alleviate some of the IDIOCY of the NipponDenso, Denso US, design. Probably worth checking, DRILLING DOWN, with your factory rep about this matter.

    Why drilling down..?

    Even to this day Lexus does not allow dealers to willing/openly disclose the existence of these highly desirable A/C operational modification capabilities.
  • wwestwwest Posts: 10,706
    These days manufacturers are relying so heavily for the A/C cabin dehumidification (Alleviates/prevents inadvertent windshield fogging on a coolish/COLD day) that the only way to prevent the A/C from operating is to open the compressor clutch circuit.

    The Lexus line now have a few C-BEST options that pertain to this, maybe Ford...
  • wwestwwest Posts: 10,706
    Sounds as if you have vapor lock, air bubble, in the one of the hoses to/from the heater core.
  • wwestwwest Posts: 10,706
    edited October 2012
    Overcharging R134a will often have that result. R134a operates at higher pressure than your original refrigerant so lower charge is used. 24 ounces vs 32....typical ratio.
  • wwestwwest Posts: 10,706

    Almost all modern day automotive climate control systems will automatically switch into "comfort mode" (should be referred to as "less discomfort mode" IMMHO). Once your cabin temperature setpoint is reached, or closely nearby, these new system will switch airflow routing to the dash, face and upper body, and provide somewhat coolish/DRY (A/C dehumification) airflow, only warm enough to "just" sustain the cabin at/near your temperature setpoint.

    Manually turning off the A/C during the non-cooling months will always help. With some systems you may have to disconnect the electrical connection to the A/C compressor clutch to accomplish an A/C function shutoff.
  • wwestwwest Posts: 10,706
    Some previous owner may have installed an Airsept(.com) EED, Ford dealers were for a time, maybe still, doing this if the owner complained LOUD enough about A/C odors or/and instances of inadvertent sudden windshield fogging.
  • wwestwwest Posts: 10,706
    Heater hose vapor lock...
  • wwestwwest Posts: 10,706
    "..air conditioning isn't used.."

    Wanna bet...?

    Unless you find a way to disable it then it will run 24/7 unless the OAT is near or below 32F.
  • So the heater and A/C in my truck only works on full blast? anyone have a solution or know what I would need to fix it? Don't want to take it in and pay a ton to get it fixed but also don't want to die of heat this winter.... Seems to be a common issue with the trucks.....
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