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Hyundai Sonata Climate Control Questions



  • True, the outside temperature may be incorrect for a short while as you first start your drive. If, however, the thing is almost always wrong (either always high or always low or both at different times during the same drive) then it is almost certain your outside temperature sensor or some associated component (the actual dash read-out for instance) is faulty.
  • Happened twice in 3 weeks, outside temp was ~ 10C (50F).

    I have 07 V6 with auto climate control. Immediately after start, the defrost control (on the driver side) automatically activated, ie, the LED lit. I believe this control automatically runs the AC too. I have a habit not to run AC while the engine is cold, also no frost/fog on the windshield so there is no need for the defrost function. I had to manual depress the button to shut it off. Just for curiosity, I shut off and restart the engine, same thing. If I remember, the LED is lit even on the accessory position (before the cranking the engine).

    Is this normal?

    I maybe wrong on this, in auto control, if defrost is required, AC will activate but the defrost LED is not lit???
  • We love our 2004 Sonata LX and have many upgrades including AUTO heating and cooling. Bought in winter of 2003. Could not get heat, so back to the dealer - nothing wrong. Each September since take long trip. Gets cold, cannot get heat unless we put it way up past 75 degrees. Each year into dealer with complaint. Stupid people, nothing wrong!!!!! Do they drive our car? Driving through mountain pass in Sept. very cold. AUTO did not work. Tried every setting. Kept track of exact setting. Had to get it close to 88 degrees to get heat. Wrote letter to dealer, had it in. Got their temperature gauge and tested cabin temp. OK, nothing wrong. AUTO not working properly but dealer said basically have to put up with that. (stupid customer again). Defrost will not work on AUTO. Did they drive car in mountains? NO. Just got little thermometer out! Recently started pelting with rain when we were out. Real downpour. Inside windshield, side windows and rear windows inside started to "fog"up. Of course AUTO was useless. Tried all sorts of settings. Seemed neither "defrost" - front or rear-could clear windows. Finally in pouring rain had to open windows so that could clear off windshield and try to keep it clear. Very, very dangerous. Been bad if we had been on the freeway. Stopped at a store. Had to sit 20 minutes first with windows up and then windows down (in rain )to clear off windows to be able to drive home. Wrote dealer, AGAIN, with copy to President of Hyundai. Woman from agency called this morning to tell us nothing was wrong with car - they have not had it in since this "fogging up incident" but based on when we had it last month! Agency would be willing to buy car back from us at a very good price and arrange for another. Told her we loved the design of our 2004 Hyundai Sonata. That did not like th enew ones. That we wanted ours fixed once and for all. We are going to write to National Transportation Board and have no idea where to go from there. ?Attorney. ?What kind.?Attorney General. Now scared to get on the road in rain, especially freeway. We feel that the defrost system, the heating system, and air conditioning system has a defect somewhere in the computer, software? or ????? Anyone else had any problems like this. This woman told us a Hyundai representative did look aat our car when it was in the shop last month. Service Manager did not say that - just said he had talked to Hyundai people in California. We are so disappointed. We love our Hyundai, but it seems that it is only suitable to dirve when it is not raining hard, is not overly hot. In other words, a "fair weather car". We are fighters. We are not going to let this go. We paid $1,000 extra to cover the computers when we bought car. We want it fixed correctly. Any help anyone can give us would be so appreciated.
  • Since we got our car in September 2003, our AUTO has not worked properly.No heat, defrost , no a/c. We have it in the shop every year but they tell us nothing wrong. When they put a therometer in the cabin they say temp is OK. However, they are not in the car when it is cold, raining and defrost does not work properly. Anyone else have these problems.
  • backybacky Twin CitiesPosts: 18,910
    So what you need to do is take the car to the dealer when it's hot or cold or raining so they can see the problem first-hand. If there is no A/C, it should be clear through their tests (e.g. holding a thermometer in front of the vents) that it is not working. Do this before the warranty expires this September!
  • Can someone help me? I have a 2006 Sonata. The "outside temperature" reading says 140 (it's only about 30 degrees outside right now). I can only get heat if I set the temp on "HI". Is there a quick fix such as replacing a fuse or something?
  • There is a TSB on this problem. Have the sensor replaced.

    Thanks go to Jerry!
  • molly44molly44 Posts: 2
    I just bought a new Sonata. The A/C does not work. The fuses are good. Compressor is not working. Could it be a bad compressor? or maybe they forgot to add Freon? Any thoughts would be appreciated
  • backybacky Twin CitiesPosts: 18,910
    I'm sure the dealer's service department will figure out the reason for the problem when you take it in to have it fixed under warranty. :)

    But, what do you mean by "not working"? Cold air doesn't come out when the A/C is on and the temperature is set to the coldest setting, for example?
  • molly44molly44 Posts: 2
    Thank you for responding. When I turn the A/C on cold air does not come out when the temperature is set to its coldest setting.
  • The AC in my 08 Sonata limited is turning on automatically. While driving to work today I started hearing an odd sound, which turned out to be the AC blowing out at max speed. (I had all my AC vents closed). So I turned it off. Then five minutes later again I heard the same sound, and the AC was again on.

    Before I head to the dealer has anyone else had a similar issue?

  • backybacky Twin CitiesPosts: 18,910
    Are you sure this is an "issue"? I've seen this behavior on multiple cars with automatic climate control, i.e. the unit switches to "max AC" mode at startup to cool down the interior as fast as possible. But then it should ratchet down as the preset temperature is reached. How long have you owned the Sonata? Is this the first time the car has done this in warm weather, with the auto climate control on?
  • Yeah this was the first time it has done this in the morning. The temp was around 77 to 78. I have never seen the AC turn on by itself before. When driving to work in the morning around 6:30am I always have the windows down. Also when driving home when it is around 98 outside the AC will not turn unless I switch it on....
    I don't think this normal behavior. Had the car for almost two years.
  • billwardbillward Posts: 154
    That sounds exactly like the behavior I would expect; you last two years sound unexpected, or as if you have the Auto-Climate setting turned off.

    But what do I know? I've got two GLSes, and neither has auto-climate control; my Father's Suburban and my FILs Lincoln Town Car both do, and they behave as you describe if the climate control is set to auto, but I'm in both of those vehicles so rarely (twice a year each?) that I could be wrong.
  • targettuningtargettuning Posts: 1,371
    I believe this is a normal situation. With all "automatic climate control" equipped vehicles there is an option to either allow the system to control the interior temperature via an auto button. If you choose this option the interior temperature is controled meaning it either cools or heats depending on the digital temp punched into the system via the dash display and the outside ambient temp. From there the system controls the AC compressor, the heater output (if needed) and the fan speed and I think air output location, dash vent, floor or both. If you (the passenger or driver) decide to vary the fan speed manually or otherwise intrude on the automatic program it (the climate control system) automatically drops out of the auto mode allowing you to pick variables manually. Thus the system becomes a manual type until the "auto" button is once again pushed. Sounds like you have been controlling this manually for all those years and somehow you accidentially hit the auto function and now are amazed it is controlling itself. I strongly believe this is normal.
  • Not sure if this would help, but I have been told that if the system is over charged it might cause this kind of problem. I recently spent 2 months trying to find out why my 04 Sonata's AC ran great in the morning when temps. were cool, but hardly ran at all when temps. were over 80 degrees. The AC would go from cool to hot and at the same time the engine performance was so bad that it felt like I was dragging something behind the car. I would have to shut off the AC completely to be able to drive the car. I had it checked at the dealer, but they found nothing wrong with the system, but I think that they only checked it in the morning at cooler temps. They said that I may have to replace the compressor, which is what the forums were saying. I bought a $40.00 AC recharge kit from AutoZone, drained the system and recharged it with "new" coolant. My car now runs great in any temps. even when it is above 96 degrees out. I believe that the lubrication in the freon was low or bad, and recharging it seemed to fix my problem completely. I have heard that there were some problem early on when the switch was made to the newer coolants, poor quality control may have been the problem. I've been told that when the dealers drain the AC system they have to capture by law so it doesn't effect the ozone, but then they recharge the AC with the same freon that they took out because freon does not go bad. Question is if the freon was a poor quality grade (low on lubrication) when installed at the factory, why would you want to recharge it with the same freon? I would drain the system completely and recharge it with the newest freon on the market, then you will know for sure that at least you are not running an older coolant that may not meet the newest requirements. From everything that I have read recently about AC systems, lack of good lubrication is the major cause for seal leaks and compressor going bad. Hope this helps you out, it helped in my case.
  • whisper1whisper1 Posts: 50
    Just to clarify ...
    Automatic AC/heat controls the fan speed, vent and recirculation. You can override them. If you do, that control is no longer in automatic mode. Untouched controls still work in automatic mode.

    For multiple drivers, there is no way to tell which control is manual/auto. The only way is to press the Auto mode and then change whatever you like.
  • Heater is not blowing hot air, the tempature is set for heat and the blower is working but cool air is comming out not hot or warm just cool. heater hose are hot and a/c compressor is not running. i have automaic climate control settings.
  • You need to verify that the door in the ductwork is moving to diverts the hot air. If the door is not moving you need to verify if vacuum is present to operate the door.
  • how do I verify these things?
  • I have the very same problem, my car is at the dealership right now. Hope it is something simple!
  • You should goto "" and find the layout of the ductwork. This should show you where the valve-doors are positioned. The heat/cold one should be by the heater core. There are others that make the air come out of the defrost vents, floor vents, dash vents and recirculate the air.

    Does you ventilation system change where the air comes out still. You could just have a hose that popped off.
  • please let me know what they say is wrong
  • ok thanks I'll check that out and yes the air does still change direction from the different areas.
  • tenpin288tenpin288 Posts: 804
    What does your temperature gauge indicate? Hot, cold, normal? It's possible your engine thermostat has failed open and your engine isn't warming up properly as a result.
  • targettuningtargettuning Posts: 1,371
    Consider that it just isn't COLD in much of the country yet...maybe chilly in the mornings. If the interior temp isn't set for 80 degrees (as an example) when the inside temperature sensor reads only 68 it isn't going to call down to the engine room for a lot of extra heater output. In other words if the difference between what temp you want in the car (via the digital temp on you climate panel) and the existing ambient interior temp isn't too great the heater isn't going to work hard to only heat the interior a few degrees
  • I have a fully loaded 1999 2.5 ltr auto Sonata. The previous owner botched a repair by cutting off the connector block from the wiring harness and connecting the cables to a non standard actuator with cable end twisting and insulating tape. As a result, the climate control doesn't work. I have bought a brand new actuator but have no idea which cable goes to which; the colour coding does not corespond. I have searched high and low for this area of wiring diagram to no avail. Can anyone help me PLEASE...
  • How many wires are there?
  • If I leave the temperature control in the cool range when turn off the engine at end of the day, I cannot get heat the next morning when turn the temperature control to heat range doesn't make a difference if I turn control to heat range before or after starting the engine. . If I leave control on heat range at night, do not have the problem. Hyundai dealer could not diagnose. Has anyone had this problem?
  • Hi
    There are 5 wires.
    The car's wiring has:
    Dark Grey x 1
    Yellow x 2
    Light Blue x 1
    Dark Blue x 1

    The wires of the actuator are:
    Red x 1
    Grey x 1
    yellow x 1
    Yellow (With dashed dark stripe) x 1 - Not quite sure what the dashed colour is!
    Dark Blue (With dashed light stripe) x 1 - Not quite sure what the dashed colour is!
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