MG ZS EV A/C won't turn on

[anuck]

It started with A/C barely cooling and noisier under the hood , but now the A/C won't turn on at all - no cold air, and the A/C compressor is silent. Where I am, it's always faster to pre-diagnose issues by oneself. My questions:

1. Would hooking up the computer show the reason for the failure? The dash shows green OK.
2. Is it possible to troubleshoot with a multimeter - just to pinpoint the issue?

Before the A/C failed completely, the "AC guy" said it's the condenser, which I have ordered and am waiting for. Of course, there may be a leak now, since the condenser was already taken out. Or maybe the compressor finally gave out since it's been most likely working under strain.

Can't really use the car comfortably without A/C here, and getting parts has additional time overhead, so would like to troubleshoot as much as possible. The "AC guy" was someone the dealer here uses . Don't ever get good things like EVs on a small island!

 

[hmadsen]

One of the components in an AC system is a low pressure cutout switch.


When the system gets low on refrigerant it will become noisier.

My guess is...

You have a small leak (condensor) so as the refrigerant is leaking out the compressor gets noisier until such a time, where the low pressure cutout will disable the compressor alltogether.

If the car is able to tell you, depends on where the low pressure cutout is located.

If it is just in series with the wiring going to the compressor, the car might not be able to tell you what's wrong, since it commands the compressor to engage, but the compressor clutch circuit has been broken by the low pressure cutout.

Only real way of diagnosing this would be to take it to a garage that does aircon service and having them apply gauges to see what pressures are in the system.

 

[anuck]

Thanks. I will have the pressure checked- the easiest thing to do. Although it was checked just a few days before the AC died so either the leak is big or the compressor died. Was interested if the computer would show anything.

 

[fred12345]

I'll join the club!

Looks like my air-con also stopped working but no idea when since like most EV drivers I try to "save" the battery charge and switch everything off unless absolutely necessary. Wrong! Looking at the top post about the air-con compressor getting louder, I have no noise coming from the "engine compartment" at all, I can hear the fan buzzing inside the car but no compressor noise of any kind. Is it supposed to be noticeably loud? I found metal air-con pipes going around the front but they were not cold to touch, normal temperature. Couldn't figure out where the compressor would be... All the controls work as normal and the heating also works as normal (2022 Trophy with climate control). Fan works on all speeds and can be adjusted. This is all in NORMAL mode, not in ECO

Just wondering (since no prior experience with air-con fails) even if the system needs re-gassing, the compressor should be pumping regardless? So there would be no point trying to shop around for the cheapest gas top up and might be better off with MG garage looking into it?

p.s. I left it running on LOW and auto setting for the last few drives and plan on leaving it on to see if it comes back to life. This morning, it smelt a bit like burning hair, switched it off and after 5 min on again and the smell was gone... hope I don't have roasted mice somewhere in the engine bay ...

 

[OriginalBigAl]

1st port of call, check all relevant fuses.

 

[fred12345]

1st port of call, check all relevant fuses.

yes, thanks for pointing it out, seen some other posts about checking the fuse and trying different settings, I'll update on how I get on with it

= fuse seems OK, took the air filter out and it's not blocked... The only thing that puzzles me is that the outside temperature is shown at 14 degree Celsius when inside the car parked in the sun is 33. At the same time my home thermometer shows 18.5 outside in the shade ...

 

[anuck]

My fuses all good. There are like 3 related under the hood, "Automatic Temp Control" under the glove box.

 

[hmadsen]

I'll join the club!

Looks like my air-con also stopped working but no idea when since like most EV drivers I try to "save" the battery charge and switch everything off unless absolutely necessary. Wrong! Looking at the top post about the air-con compressor getting louder, I have no noise coming from the "engine compartment" at all, I can hear the fan buzzing inside the car but no compressor noise of any kind. Is it supposed to be noticeably loud? I found metal air-con pipes going around the front but they were not cold to touch, normal temperature. Couldn't figure out where the compressor would be... All the controls work as normal and the heating also works as normal (2022 Trophy with climate control). Fan works on all speeds and can be adjusted. This is all in NORMAL mode, not in ECO

Just wondering (since no prior experience with air-con fails) even if the system needs re-gassing, the compressor should be pumping regardless? So there would be no point trying to shop around for the cheapest gas top up and might be better off with MG garage looking into it?

p.s. I left it running on LOW and auto setting for the last few drives and plan on leaving it on to see if it comes back to life. This morning, it smelt a bit like burning hair, switched it off and after 5 min on again and the smell was gone... hope I don't have roasted mice somewhere in the engine bay ...

If you dont need AC it saves money, turning it off, but please remember that the AC has both refrigerant and oil in the system and if you turn off the AC for extended periods of time, there is no circulation.

The problem with that is, there are a lot of o-rings in all the joints in the system and these need to be lubricated so if you do not run the system periodically, they can dry out and leaks can occur.

I was told, climate control systems often have provisions for turning on themselves for shorter periods of time, if it has not been on for a while. This is especially important in the winter and especially for the ZS EV because it does not have a heatpump function so it is never run to heat up the car, like in other cars with heatpump.