Hi everyone, does anyone know where I can buy a new Cabin Air Temperature Sensor? All I can find is 'used'ones, mainly in Spain with 15 day warranty... I cleaned up the old one and go tit running again, but aircon still not getting very cole. I had the system checked, it is full, clean and has pressure. Occasionally, it will kick in and virtually freeze your feet off, but soon goes back to pumping out hot air again... I have a 2010 1.6 TDCi Titanium Fiesta. Thanks for looking and hope that somebody might be able to help

It can blow cold but then blows hot. This is a pure guess because I haven't put test gear on the car but it really sounds like moisture in the system to me.

Hi, Thank you for your reply. I had the sysem checked last year on an automatic aircon service trolley. The guy said that it pulled out 400ml, cleaned it and put back into my car. He didn't charge because they didn't have to refill the system. He never mentioned anything about moisture.... What or how can that be checked?

The drier is supposed to remove any moisture in the system but if a part in the refrigeration  system has been replaced, for instance a new condenser, moisture can get into the system and if enough is present, the tiny drop of moisture mixed with the refrigerant, which is liquid at this point in the circuit arrives at the orifice where the refrigerant expands suddenly. This expansion causes the rapid cooling and that cooling freezes the droplet which stops any more refrigeration from coming through. This MIGHT be the failure mode. It isn't an easy thing to check as the drier window is often inconclusive, if, indeed the drier has one. The correct course of action is to remove the refrigerant, replace the drier and then hold the system under vacuum for 24 hours in order to boil off any moisture in the system before replacing the refrigerant. If that is the problem, this will be the fix. I don't know how the trolley 'cleans'  the refrigerant but if the drier has absorbed as much moisture as it can and become saturated (and I am assuming that it is fifteen years old), I wouldn't  expect the trolley to be able to remove enough moisture to make a difference so, working on an educated guess, I would first read the sensor resistance with a multimeter and see if it varied with temperature. I would search the net to find out what typical sensible readings should be and if I couldn't confirm they were sensible, I would first try a used sensor as it is unlikely to fail suddenly and it will be the cheapest thing to try before having to spend more money . If that didn't work, I would have a specialist in aircon, not the local garage, fit a new drier and vacuum down the system as outlined above. I would print this off to show to him so that if I am right he can see the diagnostic reasoning and if I am talking through my hat, he can offer alternative advice.

Edited July 18, 2025Jul 18 by anon
spelling and further explanation

Hi, Thank you for taking time to send me the above info, I have copied and pasted it all into Word and printed it off. I am planning to obtain a sensor and try it first, then follow up on what you have sent me. Thanks again, Phil

Thank you for your post. I wish you the best of luck.

Is your cabin sensor the type with a tiny fan? The reason you're only seeing used parts is 'cos you're not searching for Ford's PART number, which is called the FINIS  code. Breakers wanting to advertise bits only quote what they can see on the item as there's no way to cross reference that to the finis code for us mere mortals.  So, either call in at your local main dealership and ask at the parts store, or go on www.catcar.info and select Ford, and the model, them browse the parts. Once you've got the 7-digit finis code,  do a search like

'Ford xxxxxxx' where xxxxxxx is the finis code. Often you can find NOS  parts on eBay this way

 

 

On 7/17/2025 at 6:32 PM, Phil Janman said:

Hi everyone, does anyone know where I can buy a new Cabin Air Temperature Sensor? All I can find is 'used'ones, mainly in Spain with 15 day warranty... I cleaned up the old one and go tit running again, but aircon still not getting very cole. I had the system checked, it is full, clean and has pressure. Occasionally, it will kick in and virtually freeze your feet off, but soon goes back to pumping out hot air again... I have a 2010 1.6 TDCi Titanium Fiesta. Thanks for looking and hope that somebody might be able to help

Did you get a new sensor and did it fix your problem? I have a similar problem, changing the desired temperature doesn’t seem to affect what the system does and I think it’s because the sensor is faulty. If you set it to low or high it’s fine, presumably because it ignores what the cabin temperature is. 
The new version of the part looks different to my original, maybe it’s been re-designed.