This is a bit of a weird one, as its working. Kind of.

I use the air con every day pretty much and its almost always on. My startup procedure goes a bit like this: Demist for 2-3 until clear, than the button immediately to its left (the one where you can force it to also blow air out of the top outlets or the footwell along with the middle) for a few more mins until its nice and warm. I'm normally hitting the motorway just at this point so I hit the AC button far left which should then take over and stop the hot air blow and settle down to a nice 22-23 degrees.

Over the last day or so, hitting the AC button seems to do nothing at all, even if its set to 16 degress. If I manually use the button to set it to LOW than it suddenly blows out really cold air. Sometimes it stays cold, but I can set it to a number (16-18 etc. which should still be cold) and you can then feel it starting to get warm and back to blowing hot air back out. I should not have very hot air blowing in my face when the air con is set to 17!

It's like it has no idea what temp is anymore and can only do HOT or COLD and nothing in-between. This is my first car with Air-Con so I have no idea about the technicalities of the thing. I'm guessing a sensor somewhere has got covered in much or broke or something?

I'm into the 3rd year of the bolt-on warranty according to Perry's, hoping this isn't a pricy thing to resolve. It's been fine until now, car has around 16700 miles on it and it had its last full service in October.

Does your car have "normal" ac or full climate control?
If full climate control leave the ac on always don't turn it off especially at start up set you temp an leave it to sort itself out.
If normal ac again don't turn it off at all, especially at start up, use the temp control to control the temp only .
If you have climate control it's just possible one sensor has failed so it does not know what temp it is either inside or incoming.
Tip to keep your ac working have it recharged at 3 years old then every 2 years and NEVER switch it off this has worked for me having had cars with ac for the last 30 years

If you have the automatic climate control and it sounds like you do, it's worth noting there are several sensors that feed in to make the system decide what it's going to do.

It monitors coolant temperature, exterior temperature, cabin temperature and the sun load or brightness. At the moment it have been very cold outside and the sun very bright which can cause confusion to the system, it will think the cabin it going to get hotter than it does which causes it to blow cold air when you're asking it to be warmer.

My air con has never worked since I had the car (18 months) I've had it serviced but no joy! I've also checked the relay switch and fuse, but still no luck. My next try is going to be the pressure sensor, but I just need to find it, does anyone know where it is?

If it does not work how was it filled? Pressure sensor is easy to spot it will be in the pipework under the bonnet probably near the fire wall.
Have you had the system re gassed if so who did it?

Having had a heater control flap replaced on the climate control on our old TA under warranty, personally, if you're in the 3rd year of your dealer warranty, take it to the dealership and enquire about getting it fixed under warranty before it expires, otherwise, potentially, it could be a rather expensive fix.

Happybubbas said:

My air con has never worked since I had the car (18 months) I've had it serviced but no joy! I've also checked the relay switch and fuse, but still no luck. My next try is going to be the pressure sensor, but I just need to find it, does anyone know where it is?

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Does the compressor click on and off?

John202020 said:

Does the compressor click on and off?

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I can't hear anything when it's turned on. Do you know if diagnostics would tell me what the problem is?

Not sure if this helps, also I can't see any sign of relay 5 in the diagrams

I swapped relay 5 with the horn relay as they're both 20amp. But it made no difference. I checked the fuses aswell. I can't hear the relay click or the compressor. It has also occurred to me I have also never heard the radiator fan kick in either!

Ok so engine running heater on cold or say 18c, fan on, ac on or in auto mode, if the compressor does not click on off, first thing make sure the correct amount of gas is in the system 500g +/- 40 grams too much or too little will stop the system working after that it's a control issue faulty temperature sensors or pressure sensors relay 5 broken wire to compressor clutch an ac engineer should find the fault fairly quickly and probably not too expensive, having had ac for 30 years I would never be without it it's never off pity my wife's 500 does not have it!

Happybubbas said:

I swapped relay 5 with the horn relay as they're both 20amp. But it made no difference. I checked the fuses aswell. I can't hear the relay click or the compressor. It has also occurred to me I have also never heard the radiator fan kick in either!

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The fan will only come on if the engine is too hot or when the compressor starts so if neither compressor or fan starts it suggests no/too much refrigerant or faulty control system

John202020 said:

Ok so engine running heater on cold or say 18c, fan on, ac on or in auto mode, if the compressor does not click on off, first thing make sure the correct amount of gas is in the system 500g +/- 40 grams too much or too little will stop the system working after that it's a control issue faulty temperature sensors or pressure sensors relay 5 broken wire to compressor clutch an ac engineer should find the fault fairly quickly and probably not too expensive, having had ac for 30 years I would never be without it it's never off pity my wife's 500 does not have it!

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I think I'll get someone to look at it. I did get it serviced and gassed last year hoping that would fix it. And have put off doing it as just replaced all shocks and control arms, it all gets very costly! But now we're approaching summer I thought I'd get it looked at, as it seems to get warm very quickly inside a little car! Thanks for all your advice.

Follow the pipes from the compressor and radiator towards the bulkhead somewhere along them you will find the pressure switch screwed into the pipe

Happybubbas said:

I think I'll get someone to look at it. I did get it serviced and gassed last year hoping that would fix it......

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I'd still go to your local Fiat dealership first. If this can be fixed under warranty, it might potentially save you a considerable amount of money. I'm just speaking from experience.

frupi said:

I'd still go to your local Fiat dealership first. If this can be fixed under warranty, it might potentially save you a considerable amount of money. I'm just speaking from experience.

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Unfortunately it's out of warranty.

Clearly, I must have misread DBunx's post, he states he is into the third year of the bolt on warranty? That indicates to me it is still in warranty.....

It will be a simple fault stopping the system working , I know where you're coming from I've done one control arm and about to do other £180 for the two arms plus service parts plus two tyres for my car plus drop link plus will need to have the cam belt and water pump done this year £220, but it's worth every penny to have the ac working, cool and stress free ?

DBunX said:

This is a bit of a weird one, as its working. Kind of.

Over the last day or so, hitting the AC button seems to do nothing at all, even if its set to 16 degress. If I manually use the button to set it to LOW than it suddenly blows out really cold air. Sometimes it stays cold, but I can set it to a number (16-18 etc. which should still be cold) and you can then feel it starting to get warm and back to blowing hot air back out. I should not have very hot air blowing in my face when the air con is set to 17!

It's like it has no idea what temp is anymore and can only do HOT or COLD and nothing in-between. This is my first car with Air-Con so I have no idea about the technicalities of the thing. I'm guessing a sensor somewhere has got covered in much or broke or something?

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Hi,
so it's still COLD when asked for COLD?,
but doesn't seem to moderate the temp well,

have you got climate ( where you select a temp in 'C),
or just a twisty knob from cold to hot..with an A/C button.

I'm also suspecting it's climate..

do any of the other suggestions help..?

AFAIK there will be a little black dome on top of dash / under windscreen , it's a sunshine sensor.. if it's been covered by "SUMMAT" it's make things act a bit weird.

diagnostics do show certain air-con issues, so it's not going to be a journey into the unknown , however, do the basics( including checking the engine coolant level)..

then -( if necessary) - get the dealer to check it,
the system is pretty complex, so worth doing it in the warranty period.
Charlie - Oxford

John202020 said:

It will be a simple fault stopping the system working , I know where you're coming from I've done one control arm and about to do other £180 for the two arms plus service parts plus two tyres for my car plus drop link plus will need to have the cam belt and water pump done this year £220, but it's worth every penny to have the ac working, cool and stress free ?

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It is costly, I've also just had 2 new tyres put on, In total with all the other parts I've spent £620! The air con is on my list of things to do along with fixing a draughty window and a really annoying rattle/knocking from the rear. The other thing that is annoying is the indicator either cancels too early or too late depending on what way you're turning, but I don't think this is fixable.