Technical Interior air temperature sensor wrong temperature

[kourampies]

I have a 2011 500 with automatic climate control. It has been under 15c for some days, and I noticed that at the usual 20c setting the AC blows warm or cold.
I thought it was the common flap failure that requires dismantling half the car, but suprisingly its something else.

After connecting MES, I noticed that the interior air sensor (the one on the climate controls, behind the holes), is giving slightly higher than actual temperatures, making the climate control function erratically. Actual temperature is like 19-20c inside the car, and the sensor thinks that its around 24-25, therefore giving colder air than what it should.

Is there any fix that doesnt require replacing the hole climate controls assembly? Removing it and cleaning the sensor if its accesible? Blowing it with compressed air? Contact spray? I didn't see a calibration mode on MES.

 

[A3jeroen]

Did you try vacuuming the sensor? Cheap and easy. Maybe use a paintbrush to remove some dust.

gr J

 

[kourampies]

Did you try vacuuming the sensor? Cheap and easy. Maybe use a paintbrush to remove some dust.

gr J

I will try that. Although my 23 year old 147 has holes blocked from dust and no such issue, while the 500 has much bigger holes that look clean, but I will give it a try.

 

[John202020]

If the sensor "works correctly " but the wrong reading assuming it's always been like this and ruling out a faulty plug say, a variable resistor either in line or parallel could be used to correct the reading though to an extent this is a compromise a replacement sensor would be better

 

[kourampies]

If the sensor "works correctly " but the wrong reading assuming it's always been like this and ruling out a faulty plug say, a variable resistor either in line or parallel could be used to correct the reading though to an extent this is a compromise a replacement sensor would be better

It might have always been like this to some extent. My wife mostly drives the 500 so I haven't observed the behaviour much, but compared to my 147 and Delta where it was really easy to find the "right" temperature and leave it there for the whole season, I remember always having to adjust the 500 in order to find the correct temperature.

Is the sensor replaceable? Obviously not a fiat part, but is the part a generic electronic part and the PCB/soldering doable for someone experienced with electronics.

 

[Baglady1990]

I had to replace my sensor 2 years ago I managed to get a brand new one on eBay at the time! I’d just buy a second hand mirror that has the nipple sensor and just transfer it

 

[kourampies]

I had to replace my sensor 2 years ago I managed to get a brand new one on eBay at the time! I’d just buy a second hand mirror that has the nipple sensor and just transfer it

My problem is the interior sensor thats located (built in) into the climate controls.

 

[Baglady1990]

My problem is the interior sensor thats located (built in) into the climate controls.

Are you sure? That bit can be removed without the whole unit being removed … it’s just held in place with 4 screws …. I have the same auto system

 

[kourampies]

Are you sure? That bit can be removed without the whole unit being removed … it’s just held in place with 4 screws …. I have the same auto system

Yes I'm sure, outside temperature is absolutely correct. "Passenger compartment air temperature" is wrong.

 

[Baglady1990]

Yes I'm sure, outside temperature is absolutely correct. "Passenger compartment air temperature" is wrong.

You can replace these .. try club500italia on eBay although you may have to buy a second hand automatic unit

 

[kourampies]

I know I can replace the whole unit, and ebay.it is probably the best source. I was wondering if there's a cheaper fix and before buying I would like to see how this sensor behaves on other 500s too, just in case. It might report higher temperatures due to something else hot being nearby. In my Delta and 147 though it reports the correct temperature, and not something higher.