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Jeep Grand Cherokee A/C Heating Ventilation



  • Does anyone know if the heater cores are directional? are there any valves in the system?
  • i have a grand jeep cherokee ltd 1997
    my heater has started to blow cold air only,even when i select high coolant level is fine and the air blows throgh whatever vent i choose on the heater controls.
    my tempeature in the engine remains constant and both my radiator hoses get hot when the engine reaches temperature.
    what do you think is wrong ?
    do i need to flush the heater core ?
    will this help?
    is there a cheap fix ?
    is the thermostat ok you think ?
    please help me
    thanks in advance
  • Hello Jukeboxtango:

    Before you start changing parts.

    The 97 Jeep GC Limited has the Automatic Temperature Control system.
    This system has an onboard diagnostic function for your HVAC system.

    You can check the fault codes for the HVAC system to give you a starting point for finding out where your heating troubles are.

    To read the fault codes:
    1. Turn on the ignition switch.
    2. Turn on the ATC system.
    3. Simultaneously hold down the AC and the Re-Circ buttons.
    4. Hold them in and turn the temperature control knob to the right (CW) one click.
    5. Then release the AC and Re-Circ buttons. The “00” will show on the display.
    6. Now press either the AC or the Recirc button and the “stickman” will appear, indicating the fault code mode.
    If there are any codes in memory, the fault codes from 1 to 64 will appear.
  • narya77narya77 Posts: 4

    There is no air flow in my 2002 Grand Charokee 4.7L. When I click the AC button it lights up, I do hear a noise as if something has started but there is no air flow. I don't get air flow even when I do outside air. The mechanic is asking $600 just to find the problem.
    Is it a broken recirculation door or a broken blend door or something else? Please help.
  • blendorblendor Posts: 23
    Hello Narya77:

    Without knowing which Jeep GC model you have, if you have the AZC Automatic Zone Control HVAC system, I would recommend that you check the AZC fault codes.

    To read the fault codes:
    1. Turn on the ignition switch.
    2. Turn on the AZC system. The temperature settings should be displayed for both sides.
    3. Simultaneously hold down the AC and the Re-Circ buttons.
    4. Then turn the driver’s side temperature (Left) control knob to the right (CW) one click.
    5. Then release the AC and Re-Circ buttons.

    If there are no fault codes, the “00” display value will remain in the window.
    If there are any codes, each will be displayed for one second in ascending numerical sequence (note: no effort is made to display faults in the order they occurred). The left side set temperature display will be blanked and the right side set temperature display will indicate current and historical codes (8 historical max) presently active.
    Once all codes have been displayed, the system will repeat the fault code numbers. This will continue until the left side set temperature control is moved at least one detent position in either direction, by pressing both the A/C and Recirc buttons at the same time, or the ignition is turned off.

    Record all of the fault codes and post them.

    Also describe any symptoms you are having with your heating system.
    Like - Are you getting a good air flow thru your vent outlets?
    Like can you hear the blower working, but no air flow?
    Can you direct the air flow to the different outlet vents – defrost, floor or dash??
    Are you getting heat on both sides.

    Post your results, I’ll try to interpret them for you.
  • narya77narya77 Posts: 4
    HI Blendor,

    Thanks for your reply. Sorry I was out of town and could not see your reply.
    I did as you had suggested and I am getting error code 52.

    As far as symptoms are concerned. I hear the blower working. I feel no air when setting is at floor or direct (dash). However I feel air when it is in defrost mode. There also I don't think it is coming 100% but it is there.

    There is no heating or cooling from either side as there is no air flown on either side.

    Thanks for your help and I look forward to your reply.
  • I had a 2000 Jeep GC with the "A/C not blowing out of center ducts" in 2004. When I went to the dealership they "Removed battery tray and repaired vacuum leak" this also had to be done again in approx 2009.
  • narya77narya77 Posts: 4
    Tx Blendor! I have ordered the fix you have suggested. I will update you with results. Thanks for your help!
  • daniellouisdaniellouis Posts: 1
    edited April 2010
    I have a JEEP GRAND CHEROKEE 5.2L , 1998

    The heating is in trouble : whatever temp I request, it blows hot air, without possibility to lower the temperature.

    I have done the skech to get the errors messages from the HVAC system ; the fault codes give N° 23 and 38

    What will be the further research of the default ?

    Thank you
  • blendorblendor Posts: 23
    Hello Daniellouis:

    The fault code #23 - Door travel range to small -- is a blend door actuator drive circuit problem.
    The #38 – Circuit was open -- is a blend door feedback circuit

    It looks like you may have an actuator motor problem or the coupler that connects the actuator motor to the blend door could be broken.

    Remove the actuator motor on the bottom of the HVAC box to examine the coupler.
    While the actuator motor is off try turning the shaft of the blend door to see if the air flow temperature will change.
  • elidonelidon Posts: 1
    I live in FL & my GC blows warm, pretty soon hot air. I took it to the dealer and they said that I need to replace the compresor and in order to do that, they need to take the whole panel out and it was going to be around $1000. I really don't trust them, but, I am a girl clueless in what to do, but I would like to learn so if I can fix it, I will, or if I take it to someone they will fix it w/o riping me out. Can you give me some ideas and suggestions in what to look for. Thank you very much.
  • tom5571tom5571 Posts: 7
    Beware!!!!!!!!! First off the compressor is under the hood attached as an accessory to the engine and driven by a belt. This problem could be a couple of problems 1) a compressor failure, which will require a system flush and compressor replacement. 2) the clutch on the compressor may have failed, which can be replaced. 3) it could be as simple as low freon, caused by worn seals in the system,replacement seals cost about $5.00 plus the cost of recharging the freon. Do your self a favor and stop at a local auto parts store and ask questions.
  • narya77narya77 Posts: 4
    Hi Blendor,

    I got the kit u suggested. However, I am not able to fix the problem as the recric door is not comeing up. Do you have a video of how to use this kit and fix the problem.

  • hi guys i have a 1999 grand cherokee limited and i have no heat/ac air flow at all all the atz lights work and i got the following codes ,16,42,52,54, i did notice one day after i had shut off the vehical it sounded like the vent flaps had open and close like 5 minutes after i had shut the ignition off and had been sitting there.i do not hear the blower motor but i do hear a low level buzz like an actuator motor trying to move .can you guys help?
  • blendorblendor Posts: 23
    Hello ScotterTramp40:

    16 = Right temperature door not responding
    42 = One of four motor drivers had drive 9A9 shorted to ground
    52 = AI (Recirc) door travel range too large
    54 = Left temperature door travel too large

    The codes show you are having problems with a blend door, a blend door actuator motor, and the recirculation door.

    But the main problem sounds like you are having trouble with the blower.
    No air flow and if you can NOT hear the blower motor when it is set on HI, that is a symptom of a bad blower motor, blower motor control module or the blower wheel assembly.
  • I have a 1996 Jeep Grand Cherokee I call the money pit. We had to get the transmission fixed a couple months after we got it, We had the water in the passenger floorboard and changes a heater core (that was fun), found a hole without a plug on firewall, and finally figured it must be the drain plug on a/c. That was very interesting to find. We fixed it when we located it but not by the means mentioned here. (ours was much more difficult) Funny thing is the previous owner must have thought it was something else because there was lots of stop leak in the radiator over fill thing. That was fun to attempt to clean. Wish I would have been here sooner. Water pump has also been changed.

    Problem now is the A/C blows hot air. The heat works decently but not on floor setting. When you are driving and accelerate it just switches itself to the windshield vents until you let off on the strain you seem to be putting it in. If you turn it to vent it is hot too. Can anyone help solve my problem? I do not have the dual control that has been mentioned.

    Help .... this thing is breaking me but its paid for and that is why I keep it.
  • blendorblendor Posts: 23
    Hello Tiredofmyjeep:

    Your symptom of the air flow changing locations on acceleration, sounds like a mode door problem.

    Your AC blowing hot air, could be from a minor leak in the AC system that would only require a recharging - to a sensor in the transmission.

    Some repair manuals will give a few tests to do on your own, but if they are not the problem, you could be wasting your time or changing parts unnecessarily.

    To diagnose the AC you need the proper equipment for testing the system.
  • tuggajbtuggajb Posts: 646
    sounds as if you have a vacuum leak there is a hose that goes under your battery to the front of the jeep to a canister check that I would change it as is getting old and dont cost that much for hose
  • Unit was blowing cool to warm air. Last night added 14oz can of freon. Today, 95 degrees outside, a/c blows barely cool air. Tonight tried to add more freon,with the charging & measuring kit. This gauge registers in warning zone 70-80 as I try to add the freon. Compressor kicks on, runs for a few seconds to almost 45 seconds, then shuts down. Engine has been running for several minutes now and the a/c is blowing warm air, no cool air what so ever. What do I do now?
  • kmckenziekmckenzie Posts: 3
    - Radiator fan has stopped working. Jeep will overheat if sitting still, but is just fine when moving. Any ideas?

    - A/C is only blowing out of defrost vents no matter what the dial is set at

    Any help on these would be much appreciated.
  • woodogwoodog Posts: 3
    edited June 2010
    My 1999 Grand Cherokee Limited overheats only when the A/C is on. I replaced the thermostat before actually analyzing the problem, but have determined it is only when A/C is on. Any ideas?
  • tuggajbtuggajb Posts: 646
    ose electric fan come on when you turn on ac
  • socaldonsocaldon Posts: 4
    Mine is doing a similar thing - air is nice and cold until I drive up an incline (I suppose the engine is under strain so this is the same symptom as yours). The air just switches itself to the windshield vents until the road levels out. I did have problems with the vacuum tube but managed to fix that - only have the problem on hills now.

    I haven't got a cure as yet but am working on it - will report back if i find the answer.
  • woodogwoodog Posts: 3
    The fan comes on when it starts to overheat, but I don't believe it does simply by turning on the A/C - I'll have to check that.
  • tuggajbtuggajb Posts: 646
    needs to come on when you start ac
  • tuggajbtuggajb Posts: 646
    sounds as if the vacuum hose under the battery is cracked leads to a reservoir behind the front bumper
  • "When you are driving and accelerate it just switches itself to the windshield vents"

    I found that after time it will stay on just vent.

    I fix the problem on my 94 GC by bypassing one of the levers that controls the flap for the diction that blows at you, found behind the steering weal, made a sml bracket to space it so it was fully open. Started the jeep up to find out that it fixed the whole problem.
    Also replaced the one way valve on the block 4.99 part.

    Cant believe it was that easy.
  • woodogwoodog Posts: 3
    Double checked and fan turns on when car is started and stays on when the A/C is turned on.
  • socaldonsocaldon Posts: 4
    That sounds encouraging - thanks for the tip. Whereabouts is the lever located exactly? Does the dash have to be removed or can I access it from under the steering wheel?
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