Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Problems with Thermistor (Temp Sensor) in Hyundai Santa Fe (2002)

Hi everyone,

I was going to submit a question for the radio show, but thought I’d try the discussion boards first.

Here’s my situation. I’m the owner of a 2002 Hyundai Santa Fe with approximately 84,000 miles on it.

A few years ago (when the car was still under its standard warranty), I began having problems with the air conditioning. I would run the A/C but after several minutes of driving, air would stop flowing from the vents, even though I could still hear the compressor running. I took the car to Hyundai several times, and they always claimed that there was nothing they could do because they could not “replicate” the problem. Finally, two summers ago (just before the standard warranty expired), I made some headway… or so I thought. One of the Hyundai technicians agreed to go for a ride with me and was able to see that there was no air coming out of the vents after the driving several miles. He indicated to me that what was occurring was that the A/C was running too cold and that ice was blocking a certain hose, preventing cold air from getting to the vents. They did the repair in under a day and when I ask the man at the service counter what specifically had been done, I believe he replied that they had installed a “marshall” on it. I’m not sure if that makes any sense or not. I can look up the old paperwork if need be.

Now, flashforward to last summer. Its the first hot day of the season and I go to turn on the A/C. Air is coming out but its not the least bit cold. I take the vehicle back to Hyundai and, without looking at any other symptoms, they just refilled my A/C and charged me $170+. But when I got in the car, it still wasn’t blowing cold air out. So I took it back in and one of the service guys spends five seconds looking at it and says “oh, your compressor’s not running.” I’m still astonished that they did not notice this the first time around, but whatever. Anyway, I leave the car with them for a few hours and eventually get a call from the guy at the service desk saying that the problem part is a “thermistor” (not to be confused with “resistor” he said). He proceeds to tell me that the part itself is very inexpensive but they will need $1,000 in labor to fix it.

I was tempted to tell him to take a flying leap, but instead I politely declined his offer and said I’d try to get through the summer without A/C (in Maine, its not that hard to do).

Flashforward again to July 2009. Now my car is having all sorts of issues with caps & plugs. I take the car in, the work is done, I pay my $600 bill. I get in the car, start it and up all of a sudden the AC is running just fine, as if there was never a problem with it. I drive the car back to the dealer, call over the service counter guy and show him that its running. He scurries away to the garage and returns a minute later to tell me that the technician “jostled” the thermistor slightly to see if changing its position slightly would make a difference. He claimed they didn’t tell me because they didn’t want to get my hopes up. (To this day I am amazed that Hyundai claims to need $1,000 in labor to replace the part but the technician could stick his hand up there for free and have it working in 30 seconds). Anyway, things were good from there on, even though I have since read that the problems which went unaddressed by Hyundai in previous years A/C problems are likely what caused the thermistor to ultimately fail.

Well, now it is summertime again and, guess what? You guess it. The compressor in the A/C is not running again. At this point, I’m trying to determine which of the following avenues I should pursue:

1) Try to see if its something I can fix myself (assuming that I can reach my hand in the sample place where the Hyundai Tech did).

2) Take the car to the local mechanic at the end of my street, explain the situation to him and see if he can fix it for a small free.

3) Take the vehicle back to Hyunda and ask that they attempt to “toggle” the thermistor again, in hopes that I can get another summer’s use out of ir; or

4) Go back to Hyunda and insist that they FIX the part once and for all, and not just rig it so that it works for another year. Like I said previously, much of what I’ve encountered online backs up my assertion that if Hyundai had correctly diagnosed and repaired my previous A/C issues when the car WAS under standard warranty, the thermistor either would never have failed, or would be covered as a show of “good faith” since all of the other issues were documented. Admittedly, I tried this tactic last year, and did not get very far even after writing letters to the head of the dealership and the head of the tech service department.

Any advice that can be provided would be much appreciated. Thanks!

Well, here’s my two cents.

Take it back to the dealer, make sure you have the records from the previous services, explain the situation as you did to us, and explain that the repair should still be considered warranty repair since the original complaint was addressed while the warranty was in effect, but the possible solution didn’t materialize until later. This is probably a repeat from the last time, but it cannot hurt to try again. Be strong and firm.

If they don’t agree with this, at least ask to have a technician show you how to ‘toggle’ the thermistor as he did before. Chances are, the contacts in the wire connector to the thermistor are dirty, and ‘toggling’ it restores a good enough electrical contact to get you through the summer. If the thermistor connections are easy to get to, maybe a shot of electrical contact cleaner can solve this problem.

If you still cannot get it to work, then visit the local mechanic and see what he has to offer.

If you do decide to tackle this yourself, I highly recommend looking on eBay or for a shop manual from Hyundai for this SUV. These are the same books the dealer mechanics and the local mechanic should have to do a myriad of repairs. They typically cover repairs for everything, bumper-to-bumper and have the most complete information available.

where you able to locate the thermist0r on your santa fe

look at the diagram…