C205 - AC suddenly stopped working

[FreshFromTheGrave]

Man 2 years with this car and not one thing went wrong, 2 weeks of storing it outside instead of underground after moving and my streak is broken

So AC was working fine in the morning, it sat in the sun the whole day on the 2nd hottest day of the year and by evening it wouldn't work. I tried the button on the console which didn't want to light up, if I went to the climate menu and tried to turn on the AC there it would briefly tick the box for a second, before unchecking itself again.

What are the odds that it just needs to be regassed? Is it possible for it to be a sudden change like that? I'd have thought it would be a slow decline in cooling performance instead of a sudden failure. Car is from 2016 and it's not known if it's been recharged before.

Is my best bet a Mercedes specialist? Does anyone have any recommendations around Windsor/Maidenhead/Reading area?

Thanks all!

 

[Petrol Pete]

It might have been losing a bit of 'gas' for a while and the other day day the pressure went just below the threshold to 'trip' the low pressure monitor and shut the system down to protect itself.

Did the LED on the console button flash at any time when trying to operate the A/C ?

MB specialist not really required for a 're gas' , a quick system pressure check is all that required before moving forward , that can be done by any reputable local garage.

Let us know how you get on .

PS . What a carp time for your AC to pack up .

 

[FreshFromTheGrave]

It might have been losing a bit of 'gas' for a while and the other day day the pressure went just below the threshold to 'trip' the low pressure monitor and shut the system down to protect itself.

Did the LED on the console button flash at any time when trying to operate the A/C ?

MB specialist not really required for a 're gas' , a quick system pressure check is all that required before moving forward , that can be done by any reputable local garage.

Let us know how you get on .

PS . What a carp time for your AC to pack up .

This is what I'm hoping! The red light didn't flash at all when trying to switch it on though, the only thing was if you did it in the actual climate control menu then it would tick and untick the box after about a second.

 

[OldskoolRS]

We're quite close to you over Wokingham way: My wife had her old SLK checked and re-gassed by a local guy who was really good. We're trying to (re) find out who it was as my Alfa needs checking as the engine fan is on all the time (which indicates a possible AC fault, confirmed with my code reader). Once I manage to get out of her who/where it was I'll post back here.

 

[Oleks1992]

George Fraser mercedes isn't that far from you as its in Uxbridge. Very good knowledgeable team

 

[FreshFromTheGrave]

George Fraser mercedes isn't that far from you as its in Uxbridge. Very good knowledgeable team

That looks pretty good, thank you for the rec! Looks easy to get to, online booking (sort of) and a waiting area so I don't need to figure out how to get home lol.

 

[Oleks1992]

That looks pretty good, thank you for the rec! Looks easy to get to, online booking (sort of) and a waiting area so I don't need to figure out how to get home lol.

Yeah definitely

 

[Uky]

I would like to suggest an inspection of the radiator and all hoses/joints in the
rest of the system.

Even if the system has never been repaired (where it is filled with a UV-florescent additive)
it is possible to spot a leak by looking for a wet greasy spot somehere. Particularly
the radiator but also connections to and from all other parts of the system.
The greasy spot is the compressor oil leaking together with the AC media.

 

[Mickw212]

tried the button on the console which didn't want to light up

If all the switches AC heated screens Auto etc did`nt light up on start up & your ECO Stop/start does`nt work?, like mine did`nt today i`d be looking at your small battery in the boot or wherever it is on your model.

I had this happen last year & after checking on here the auxillary battery was deemed the culprit. I bought one, fitted it & the panel lit up & i had A/C fully working. I didnt get rid of my old battery so its now on charge. I`ll fit it in the morning to see if it`s my problem & maybe yours?? If it is at fault then my problem is to find out what charges this battery??

All the best

 

[FreshFromTheGrave]

If all the switches AC heated screens Auto etc did`nt light up on start up & your ECO Stop/start does`nt work?, like mine did`nt today i`d be looking at your small battery in the boot or wherever it is on your model.

I had this happen last year & after checking on here the auxillary battery was deemed the culprit. I bought one, fitted it & the panel lit up & i had A/C fully working. I didnt get rid of my old battery so its now on charge. I`ll fit it in the morning to see if it`s my problem & maybe yours?? If it is at fault then my problem is to find out what charges this battery??

All the best

Hmmm actually my start/stop doesn't work even though it had a new main battery put in last year But I didn't think the capacitors in the W205 had much 'responsibility' that it would affect the AC. Worth looking into though!

 

[Mickw212]

But I didn't think the capacitors in the W205 had much 'responsibility' that it would affect the AC. Worth looking into though!

Just fitted my original now fully charged auxillary battery & i now have A/C panel fully functional, as in ALL heated screen/Auto/high/low temp functions work. Hope that helps you?

I still don`t have ECO in Green so this points to my main battery which i believe to be original? However you stated you replaced that one so im gonna put that on charge tonight to see if that works before buying a new one. Try charging your auxillary battery mate to see if that helps? I bought a C-Tek charger & that took maybe 1hr 30 mins to charge mine which i thought was quite amazing but maybe i`m easily pleased . I bought my auxillary battery from Mercs & i think it was about £115?? Takes 5 mins to change & very easy to do.

 

[Mickw212]

Update,
As my car sits unused for weeks on end i decided to buy a new main battery. Fitted it today & ECO function has returned. Eco light did`nt turn green straight away. it took a five min drive for this to happen.

Hope the auxillary battery sorts your car out.

All the best.

 

[FreshFromTheGrave]

Update,
As my car sits unused for weeks on end i decided to buy a new main battery. Fitted it today & ECO function has returned. Eco light did`nt turn green straight away. it took a five min drive for this to happen.

Hope the auxillary battery sorts your car out.

All the best.

My start/stop worked as soon as I had the main battery replaced and then it stopped again a few months later for an unknown reason. It could be the capacitor (205s have big capacitors rather than batteries) but there were no warnings for it like the main battery had. The capacitor is still quite small though so I'd be surprised if it had any load on it for the AC. But it's still a clue to pass onto the tech when it comes to that!

I should get myself an icarsoft or something

 

[FreshFromTheGrave]

Guys I finally got this fixed! So I wanted to take it to Star in Reading but they were booked up for like a month, so I went to check all the dealer's slots again and Beaconsfield had a few slots only a couple days away so I just took it there.

It was a pressure switch! So that's been swapped and it's been regassed and it's cold as ice again. £413 in total for diag, the switch and the regas which was the most expensive part of that. Probably more than it would have been at Star but it's hardly bank breaking so I'm happy enough I was beginning to get a bit worried cos I was listening in on a lot of other conversation and the amount of customers getting told they needed tons of work to get the car through MOT and the tones of voices being used were very off-putting But it was all fine for me, no upselling or crazy issues being brought up.