My Jeep is HOT!

    So when I first bought my jeep back around Thanksgiving, some of you may remember that I submerged it almost right after I bought it (T-Day weekend run). Ever since then my Heat / AC has not worked properly. It only operates in HOT mode, regardless of what temperature setting is chose, or even if AC is selected as opposed to heat. What does work is the blower level, I can choose any of the 4 levels and it pushes air at the appropriate speed.


    From what I vaguely understand, there is a switch under/behind my glove box that controls part of this. Can anyone confirm this? Has anyone got any info on diagnosing this / fixing this type of problem?


    I've searched, but most articles are on engine temp which doesn't help.


    Thanks!

    Hope this helps, sounds like you may have a blend-air door motor problem. The heater and optional air conditioner are blend-air type systems. In a blend-air system, a blend-air door controls the amount of unconditioned air (or cooled air from the evaporator on models with air conditioning) that is allowed to flow through, or around, the heater core. A temperature control knob on the heater-A/C control panel determines the discharge air temperature by controlling an electric motor, which moves the blend-air door. This allows an almost immediate control of the output air temperature of the system.

    there should be whats called a blend door which moves to regulate air coming from the heatercore or the evaporator. If your door is stuck all the way closed on the evaporator side you will only get heat from your vents. I'm not sure how jeeps work but on the landrovers at work they have a little electric motor that moves the door if you sunk your jeep with this kind of motor you may have killed it

    Found this too: If the heater outlet air temperature cannot be adjusted with the temperature control knob on the heater-A/C control panel, the following could require service:


    The heater-A/C control.
    The temperature control motor.
    The blend-air door.
    Improper engine coolant temperature.

    Are these parts on the inside or the outside of the Jeep? Back behind the middle console?


    Quote from Tech517


    Found this too: If the heater outlet air temperature cannot be adjusted with the temperature control knob on the heater-A/C control panel, the following could require service:


    The heater-A/C control.
    The temperature control motor.
    The blend-air door.
    Improper engine coolant temperature.

    Is it possible the giant black ball (vacuum), that has been rolling around in my engine compartment because it has no home anymore, is actually important?


    http://www.naxja.org/forum/sho…17819&highlight=blend-air


    Quote

    You, my friend, have a vacuum line leak to your HVAC controls. The vacuum line that operates the air doors runs from your HVAC controls through the firewall just under the pink (heater control valve) line along the passenger side fender and under the battery to the vacuum reservoir (the "black bottle"). when the lines run under the battery tray they tend to corrode, break, split, whatever and a leak will develop there. Trace those lines and if you find a leak, split, etc. fix it (as in repair, not duct tape) and your air/heat will miraculously flow out the front vents.

    On my '00 XJ, the blend door motor is in the passenger side footwell in the bottom of the heater box, next to the floor vent. Has an electrial connector and three screws hold it in.I'm not positive but I think the vac. lines only control air displacment(defrost,middle or floor) ,the temp. is controled by the blend air door.

    mine is only blowing hot air... whatever temp the air is in the engine compartment if I'm not moving. a little cooler if I'm at speed. is the A/C compressor kicking in? it should be running almost continuously, shutting off once or twice a minute. if it's kicking on and off a lot, you don't have enough oil in it. if it's not turning on at all, it's empty.


    pep boys messed up my system last year, I haven't gotten around to fixing it, just recharging the system every couple of weeks when I want colder air.

    Jerry / Whatevah

    2020 Gladiator Mojave - 33" Falken mud tires, LoD side steps, Zroadz bed rack, Quadratec QRC winch bumper, Superwinch EPi 9.0, Kleinn on-board air, Kleinn air horns, lots of lights, Yaesu ham radio with GPS tracker.

    Gone- 2012 JK Rubicon with stuff. Long gone- Long-arm 2001 Cherokee with stuff.

    Have you checked the compressor and coolant level? That's where I'd check first. My wife's grand had this problem and it was something called the "AC head". Not sure what that is but that's what the dealer replaced (all under warrantee).

    Member since 2000

    Jeeps Owned'79 CJ5:

    Specs-

    - 258 I6

    - '93 Cherokee fuel injection and HO head,

    - bored 30 over

    - with 4x4 cam

    T18 tranny with granny low / Dana 18 t-case

    Dana 44 front and back from late '70s Wagoneer, both locked and loaded with 4.88 gears

    SOA on modified YJ springs with shackle reversa

    Fiberglass tub with 6 point cage mounted to the frame


    2015 Grand Cherokee Limited
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    those who need A/C units recharge. I am about to pick up a couple of used A/c machines from one of my accounts. I'll have a R 12 and R 134 machine soon. Just got rid of our lift to make more room in the shop for repairs. :bang: Looking to get another one when I get a trade and will let u guys know. Now for the R 12 u will need so supply the Freon for that one. I can't use my pops. It's gold. Now I have some 134 laying around and I'm sure the machine will have some when I pick it up. :tup:

    84 Cj 7 AMC 150, 4.5" BDS Lift, Twin Stick, BF Goodrich 35s...


    98 Grand Limited (Wife's)
    ~Always interested in trades~

    never heard of the term A/c head. they have a compressor, dryer, reservoir, and a TXV that controls the pressures. Maybe that is what they are calling the TXV. About how much was the part if I may ask. I know it's under warranty, but they should have giving you the cost and your balance would have been zero.

    84 Cj 7 AMC 150, 4.5" BDS Lift, Twin Stick, BF Goodrich 35s...


    98 Grand Limited (Wife's)
    ~Always interested in trades~

    Some compressors are like air compressors, and like engines which have a head, just like an internal combution engine....that is what I would guess they were referring to. probably had a bad gasket or a warp.

    well I never heard of them repairing the compressor. they just normally replace them. then they have to replace the dryer cause when a compressor goes, it turns the freon to acid! Very bad! :upset: But they can just pull a vacuum, clean out the system and put fresh freon in up in there and your good to go. ;D

    84 Cj 7 AMC 150, 4.5" BDS Lift, Twin Stick, BF Goodrich 35s...


    98 Grand Limited (Wife's)
    ~Always interested in trades~

    Just checked on my '00 XJ. If you start the jeep, turn climate control on, look at the blend air door motor and turn the temp dial from hot to cold you should see the silver circle on the motor turning clockwise and counter-clockwise. If it does not turn and you have a volt-meter handy see if your getting voltage from climate control unit. An easier way may be if it does not turn find a buddy with a known good one and plug his into your vehicle, if it turns you know you have a bad motor. You also may be able to turn yours with a flat head screw driver,Dont force it though the blend door itself may be stuck and you could break it.

    that is the ticket....if the compressor is a semi-hermetic type, then it has a replacable head, which could be the case...


    AC systems are easy once you know the basics...

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