Technical AirCon not working - 2014 500(S - TwinAir)

[maxerhard]

My AC has stopped working, I think it was a bit intermittent before. I took it for regassing initially but they were unable to get it working (I'm not sure if they left it in the filled state, more on that later...)

On further investigation (I wish I had done this first), I notice the compressor is not clicking in at all. I've checked fuse 19 in the box next to the battery and relay 5, which both seem OK. I tried shorting the relay contact pins, the compressor now spins (it doesn't get cold, or at least not significantly - no gas? - there is a slight whining sound inside).

On the basis of what I've checked so far, I'm guessing the signal from the controls is not getting through. I might try checking what's on the coil contacts for the relay, I checked with a voltmeter although this is produces confusing results (might try with a light bulb or LED).

It's the model with climate control (I can now see the disadvantages of this, although it was good when it was working).

I'm new to these forums, apologies if there is are exhaustive previous similar discussions but I couldn't see anything that close.

 

[PuntoHowTo]

Modern air con systems use a pressure solenoid valve to control the flow of gas and pressure. This can be a common failure point on all cars.

If you don’t know the current charged state of the system it’s going to be really hard to say what the problem is

 

[jrkitching]

My AC has stopped working

On a car that's more than 10 yrs old, the cost effective solution is to just leave it that way. If regassing hasn't solved the problem, the cost of repairing it is likely to be disproportionate to the value of the car.

 

[steveras57]

My money would be it needs re-gassing and the pressure sensor is stopping the system working! why not go to one of the many places (kwik-fit etc) that advertise a free air con check and they will test the system to see if it will hold pressure if its good they then ask you if you want to pay for the re-charge? if its not good they dont usually charge for the testing!

 

[jrkitching]

My money would be it needs re-gassing and the pressure sensor is stopping the system working

That was my first thought also, but it seems the OP has already done that.

I took it for regassing initially but they were unable to get it working

 

[steveras57]

That was my first thought also, but it seems the OP has already done that.

SO if a component has failed or there is a leak it is not economical to repair! did the place the OP took it to for re-gassing actually tell him it wasn't holding a vacuum I wonder?. and has a different (new ) relay been tried?

 

[porta]

It’s always worth getting the actual fault found, then it’s the cost of repair/replacement that would affect the cost/benefit…the way the climate/weathers going I’m tempted to get my Cherokee XJ’s AC working, if only to sit in it in my underwear, I hate the bloody heat!

 

[John202020]

Look at the condenser is it knackered it's quite possible that there's a leak, however they should have pressure tested the system, also a lack of vacuum to remove what's in also suggests a leak, any proper ac specialist will be able to check the system?

Note to anyone with a car with ac, never turn it off, this will ensure ( with correct servicing) it works as long as possible.

 

[porta]

Yup, the panda and renegades AC are on year round, work just as well as heat as they do cold

 

[Mike1alike]

The compressor not clicking sounds very much like a blown off Pressurestat. It will help you a lot to connect a diagnose and read what there is about AC, if there are any errors stores, what pressure is in the system.
You should definitely know if the system is filled with refrigerant or not. If the system is not filled with refrigerant it will never work, you know that, right?!

 

[The Panda Nut]

My money is on a leak. We had our condenser replaced and at a then £250 repair cost, I was ok with it. If you have low gas pressure it wont work. Panda condensers are prone to failure due to corrosion of the condenser radiator. Parts are reasonably cheap on Ebay. Look for Denso they were OEM suppliers.

 

[blue monkey]

Most AC places can check for leaks as the refrigerant gas escape marks can be spotted under UV light. It's always worth getting a quote as AC is a must in summer

 

[John202020]

Most AC places can check for leaks as the refrigerant gas escape marks can be spotted under UV light. It's always worth getting a quote as AC is a must in summer

Also a inability to create a vacuum indicates a leak even before trying to fill?
Part of the reason the aluminium condenser fails is, when in winter people never use the ac, it just sits in a moist often salty state corroding away, at least when it's always on it gets dried out?

 

[maxerhard]

Some good answers. I'm leaning towards some issues with pressure sensors (and possibly also lack of gas, whether that was the initial issue or not, who knows...)

The pressure switch(es - how many?) do(es) not seem very accessible, or at least I haven't found them so far. I agree with those saying a full repair may not be worth it. So far I haven't paid anything (KwikFit didn't charge as the refill didn't fix it).

I might attempt a bodgy semi-fix, wire up the relay contact pins to a switch that I can turn on and off (and regas it again). If there is a DIY method of measuring the pressure in the system, this might give me an idea of whether this is worth pursuing.

 

[maxerhard]

One additional thing worth mentioning.

Out of curiosity (with the engine off) I tried turning the compressor over by hand. This is much easier than I was expecting, can do whole turns quite easily. It's obviously moving something around inside but I would have expected more resistance.

 

[PuntoHowTo]

One additional thing worth mentioning.

Out of curiosity (with the engine off) I tried turning the compressor over by hand. This is much easier than I was expecting, can do whole turns quite easily. It's obviously moving something around inside but I would have expected more resistance.

For the second time, modern ac compressors use a pressure solenoid valve to control the flow of gas. There is no “clutch” as in the past. You can’t just bypass a pressure switch or trick the aircon into running because you would need to have control of that electronic valve.

If there is a known good charge in the system and it’s still not working the next thing is potentially diagnostics to see if any faults are recorded or more importantly to see if the compressor is changing the pressures in the system when the ac is switched on, and if so by how much.

I would assume if kwikfit tried to charge it and they couldn’t get a vacuum then the first then they would have told you is that there is a leak.

The fact they just didn’t charge you and sent you on your way suggests it was more complicated than a simple leak.

 

[maxerhard]

For the second time, modern ac compressors use a pressure solenoid valve to control the flow of gas. There is no “clutch” as in the past. You can’t just bypass a pressure switch or trick the aircon into running because you would need to have control of that electronic valve.

If there is a known good charge in the system and it’s still not working the next thing is potentially diagnostics to see if any faults are recorded or more importantly to see if the compressor is changing the pressures in the system when the ac is switched on, and if so by how much.

I would assume if kwikfit tried to charge it and they couldn’t get a vacuum then the first then they would have told you is that there is a leak.

The fact they just didn’t charge you and sent you on your way suggests it was more complicated than a simple leak.

I don't doubt this may be the case for some cars but mine definitely does have an AC clutch. When I first started looking at this, the centre of the pulley on the compressor was not spinning. When I bypass the relay contacts there is a click and the whole thing starts rotating.

As regards KwikFit, I can't remember the exact words but I don't think a leak was explicitly mentioned, just that I should consult a specialist.

 

[Mike1alike]

If there is a DIY method of measuring the pressure in the system, this might give me an idea of whether this is worth pursuing.

Yes, there is. Diagnoses tool (ELM) and MES shows you the AC pressure.

 

[John202020]

Don't "test" the compressor any more or you'll bust it. Running without gas a bad idea