[pemdas1972]

I have run into a probelm with the Automatic Climate Control in my 2002 Santa Fe. Usually when it is 90F outside I tend to keep the temperature at 68 degrees. The way it rutinely works on the auto setting the air is cold with recirculate engaged and the fan speed on high until the cabin cools down. These last few hot days it doesn't work that way anymore. Now when i keep it at 68 degrees the fan speed is medium low and the recirculate is off and of course the air coming out of the vents is not sufficient enough to cool the cabin down. When I set the temperature all the way down to the lowest setting 62 degrees it gets cold again with recirculate engaged and the fan speed goes to maximum. I am suspecting it is a dirty or bad temperature sensor in the control unit but that is just a guess. For now I am keeping the temperature at 62 and running it on manual. When I push the AMB to get the outside temperature it appears to be accurate but I don't know if that is an indication that the outside temperature sensor is working at 100%. Does anyone have any suggestions on what I should check or replace?

 

[peter9505]

Hi, I`d check the cabin sensor first but could also be dirty filters. The outside sensor located behind the front bumper is not easy to get to but might also be responsible for setting cycle speed. You must take into consideration that a car A/C will be able to give you 20 degrees Celsius difference between outside and cabin temp easily but on hotter days it has to work much harder to get those degrees down, so if this happens on super hot days and goes back to normal on regular days with lower humidity I wouldn`t worry.

 

[lovemysantafe]

Start with the easy approach and get one of those little compressed air canisters that people use to blow out their keyboards. Use that to blow all the dust out of the temperature sensor on the climate control faceplate. That has solved a majority of the problems people have with the automatic A/C.

 

[pemdas1972]

@lovemysantafe

I did as you suggested and used a can of compressed air through the climate control faceplate and noticed an improvement but still not 100% so what I did was pull the unit out to see what is going on behind it. There is a small fan in front of the sensor that sucks air in through the faceplate to the sensor. What I ended up doing is feeding the red extension tube of the air can through the center hole of the faceplate until it ended up between the fan blades and blew it out. The closer proximity to the sensor cleans it out more effectively. Works good as new again. If that had not fixed it I would have sprayed some electrical contact cleaner to see if that would have fixed it since there would have been nothing to lose at that point. Thanks for the guidance!

@Peter9505

I read up on how the climate control works and as you stated the system depends on both the outside ambient temperature sensor right behind the front grille as well as the "in car sensor." Sounds like such a general name for a sensor but that is what it's called. That sensor is available at the dealer for about $110.

This is the first time I have ever had an issue with the automatic climate control system since I bought the car in October of 2001 so no complaints here as far as the reliability of this system is concerned.

If anyone wants to run the onboard diagnostics for this unit all you have to do is hold down the AUTO button and push the AMB button 4 times within 2 seconds and release. It will give you any error codes stored in the unit. To exit the diagnostic mode just hit the off button.

 

[lovemysantafe]

Glad you were able to get it fixed. And it's amazing how a little dust will just gum up the whole operation, isn't it?