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Acura MDX Heating and Cooling Questions

ronnessronness Posts: 1
I have no power and air to my rear heat/AC on 2003 MDX touring. I do however have regular power to the front unit. The dash board light comes on to activate the rear unit, but no air hot or cold. I notice too that the the two air directional buttons no longer light up.
I have tried to look for a bad fuse under the hood, but have not notice anything unusual. The only strange thing I can recall happening some time ago was while driving slow, a loud squealing noise underneath the hood caused the the engine check light to come on briefly. I turned the car off, looked underneath the hood, but could not find any loose belts or parts. I turned the car back on, and everything appeared ok. It wasn't to much later that I came to realized
that the rear unit had no air or power. Does anyone have a clue as to what might be the problem before I take it to the dealer? Thanks in advance


  • dmz616dmz616 Posts: 17
    I have a 2002 MDX touring with 112k miles and just found that the rear AC unit is not working, DTC indicates a problem with the blower motor. Both fuses are ok. I do not recall any noise like you described. Did you find out what the cause was in your vehicle? Any help before I take it to a dealer? Any help from Acura?
  • knudsenjknudsenj Posts: 4
    I had this same problem on our 2002. The fix is relatively straightforward if your handy with a soldering tool.

    Here is a link to a thread with full details. Search through the thread for pictures of the repair...

  • dmz616dmz616 Posts: 17
    Thanks for the links. Got the thermal cutout from Digi Key, 0.45 plus shipping. Fiix took about 30 - 45 minutes. Blower screen was very dirty. Do not know why Acura/Honda did not make cleaning the filter a maintenance item. Called the 2 Acura dealers in the area, they said there was no recall or TSB on the problem. Could not find one online either.
  • dg110270dg110270 Posts: 1
    I've got the same rear air problem with a 2002 MDX. I cliced your link to the fix but it did not work. It goes to a Rick Ashley music video. can you send a new link to the fix instructions?
  • I have this problem, but the previous mentioned link doesn't work? Someone mentioned the thermistor, getting it from "Digi Key"? Does anybody have the instrucutions on the repair that can be added to this forum.

    Thank you, Dave
  • Do you have the details on replacing the thermal cutoff? What part to order and from where?
  • dmz616dmz616 Posts: 17
    The part that is soldered inside the transistor assembly that went bad is a Thermal Cutoff (like a pigtail fuse) rated at 114C, 2A,/250VAC. Digi-key (800-344-4539) part number P10920-ND. Piece price was around $0.50, ordered a few since postage was a couple of bucks. Take the vertical carpeted piece out at the bottom drivers side of the center console being careful not to break the plastic clips. See the wire vent; clean this as the clogged vent is what causes the overheating. To the rear of the vent, toward the rear of the vehicle, see the plugged in transistor assembly. To remove, twist it. It may be hard to remove, had to use a pair of special pliers that my honda guy had, but it may come loose without needing them. Unsolder the thermal cutoff & solder in the new one, etc. We try to remember to turn off the rear unit at the dash when nobody is in the rear seat, especially on a long trip. Do not know wht Acura did not at least make the cleaning of the vent a maintenance item!
  • Thanks for the detailed item and installation, I'll let you know how it goes.
  • dose anyone have a detailed diagram on council removal?
  • The repair for my 2003 MDX, were exactly like the 2002 MDX mentioned earlier. The transistor assembly is removed by turning it clockwise about 1/4 turn. The thermocouple is acessed by removing the plastic cover and the metal heat sink. There are 2 screws on the end, and 1 screw holding the power transistor firmly against the heat sink. Thermo-coupler is soldered in two places and bent to fit along the top of the power transistor. make sure you leave some of the thermal grease so the new thermo couple makes a good seal against the heatsink and transistor. The thermocouple leads should be insulated before you solder it in place.
  • I replaced the thermal cutoff and the rear a/c now blows just fine. So fine that I cannot get it to turn off, even with the front controls off and the front a/c completely OFF! The rear rheostat doesn't function either. Could there be a short in the transistor? I'm thinking the rheostat is/was broken and shorted the thermal cutoff instead of overheating the rheostat--any thoughts????
  • usalianusalian Posts: 1
    my blower also wont turn off after i replaced the thermal cutoff. Anybody has any idea why it wont turn off ? i get cold and hot air when i turn the temprature know. But the fan knob does not seem to control the blower anymore ?
  • Just trying to help out here. If your front or rear A/C just stops blowing one day and had been cooling fine, then it might be the thermal cutoff inside the transistor assembly, which is a DIY project. There are instructions here, and even better ones at, at the Problems tab. My thermal cutoffs arrived yesterday from Digikey, and after soldering each of them in the assembly, both the front and rear A/Cs are back in business. If you cannot do the soldering, then even replacing the entire assembly will save you a lot of money over having the dealer install it. Hope it works out.
  • bobc70bobc70 Posts: 10
    I have a 2005 MDX and just recently noticed when I put the heat on I get cold air from the front vents but hot air comes from the rear vents, I turned the AC off and it's the same, whether it is in Auto Mode or Full Auto mode? has anyone had this problem
  • danlydanly Posts: 1
    Did you get an answer... I have a same problem with my MDX 2003. Please help. Thank you
  • my AC is not working but when i get on the interstate and have to drive a good distance it will kick on and will blow cold air. when i am driving around town it just blows hot air. i checked all the fuses and they are good. the fans work fine when the AC is turned on but no cold air??? any ideas?...(out of warranty, ~108000 miles)
  • wwestwwest Posts: 10,706
    If the engine/coolant is "tending" toward overheating the A/C compressor will be disabled.......sounds as if your radiator cooling fan(s) might be on the fritz.
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