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Discussion Starter #1
My first post, hello all and thanks for the tips on the other posts.
Had the ZS EV since March and it's generally been great. Since the warmer weather, I've noticed that the AC system shuts down completely if the fan speed is put greater than 3. The other settings make no difference (temperature/re-circulation/AC on or off). It will sometimes even shut down when the fan speed is on 3. Only on settings 1 and 2 will it continue to run.
The dealer is checking the 12v battery level tomorrow as they think that might be the fault. I thought the 12v battery was charged when granny charging or via the HV battery? They say they might need to charge the 12v over-night.
I saw a similar issue on a previous post (davesul) that was resolved with a firmware update, and wondered is anyone else has had this and resolved it?
Thanks all.
 

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is this when you're driving or parked up?
if the vehicle is fully on, then the 12V battery is charged up. it's only if you turn the car on without pressing the brake and the start button is orange that it won't necessarily be charged.

on charge, the 12V battery is charged.
 

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Discussion Starter #3
Hvac shuts off when I'm driving.
Thanks for confirming that the 12v is also being charged.
 

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Discussion Starter #4
Quick update - went to the dealer today to get the AC issue investigated. 12V battery seems to be fine. Unfortunately, their computer was broken and wouldn't connect to MG, so they couldn't diagnose the fault. Also, they are reluctant to do any updates as they had two cars 'damaged' by updates last week. They are going to call MG and ask for advice.
PS My 1000mile average is 3.8kWh/mile - normal driving, no attention paid to consumption, e.g. AC on (low due to the fault!), etc.
PPS Price for a replacement cabin filter (PM2.5) is £35 (not activated carbon). Seems a bit expensive as this was typically £10-20 on my old car (BMW) which had a bigger filter and was activated carbon.
PPS Car charged at Electric Blue on fast charge on 1st attempt - around 44kW, went from 40% to 80% in about 20mins. MG not listed on their app, so they told me to pick any car. Bonus is that it is free until the end of June.
 

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Discussion Starter #6
I drive in normal mode mostly, fault is very repeatable; any fan speed over 3 and the whole AC system shuts off. The only way to get it to work is to shut it off and on again with the fan speed on 1 or 2.
Dealer has been asked by MG to find out the software versions on ecu, etc., but they haven't been able to fit me in yet.
 

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I drive in normal mode mostly, fault is very repeatable; any fan speed over 3 and the whole AC system shuts off. The only way to get it to work is to shut it off and on again with the fan speed on 1 or 2.
Dealer has been asked by MG to find out the software versions on ecu, etc., but they haven't been able to fit me in yet.
Looks like you will be getting the new update FOC anyway now.
Bugs should be eradicated with a software update is my guess.
Another owner had a very similar fault, software fix for the win !.
 

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Discussion Starter #8
Quick update...

The problem was fixed by a replacement resistor/relay on the AC system. MG head office were quite confident that this would fix the issue, so probably has occurred before. This was done yesterday and all works fine. I've noticed quite a few people have had this problem, so hopefully this solution might be worth considering. Nothing to do with the 12v battery.

Shame that it took so long to fix (part took a long time to arrive) and that we've now missed the chance to use the cold AC on full!
 

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Quick update...

The problem was fixed by a replacement resistor/relay on the AC system. MG head office were quite confident that this would fix the issue, so probably has occurred before. This was done yesterday and all works fine. I've noticed quite a few people have had this problem, so hopefully this solution might be worth considering. Nothing to do with the 12v battery.

Shame that it took so long to fix (part took a long time to arrive) and that we've now missed the chance to use the cold AC on full!
Glad to hear it is now fixed !.
Thanks for posting the required fix as other members encountering this issue have a direction to follow.
 

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Resistor failure has been reported elsewhere.

Had similar issue with a Honda 15yrs ago where I could have the fan on speed 1 or 4 but not 2 & 3. That was also a common resistor failure.
 

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Resistor failure has been reported elsewhere.

Had similar issue with a Honda 15yrs ago where I could have the fan on speed 1 or 4 but not 2 & 3. That was also a common resistor failure.
Similar here.
Had a 3 series BMW with a four stage heater blower switch.
One day it just decided to give out max power on all four settings !.
Heater resistor unit placing inline before the motor was the problem,
About £30 and about 20 mins to fit is I remember correctly ?.
The MG must work in a slightly different way though, because usually on other cars you lose all of the slower speeds that the resistor controls, then the motor only spins at max power as a fail safe.
On the MG it appears to be failing at the higher speeds when you would expect the resistor to be doing very little to reduce the load ?.
Maybe some body else who is more qualified in things electrical can shine a bit of light on this subject ?.
Is the problem the length of time the motor is running that produces the problem and rather the load on the resistor ?.
Either way it’s a bit like the circuit breakers in the early Rolec wall boxes, not fit for purpose and burns out prematurely !.
 

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I drive in normal mode mostly, fault is very repeatable; any fan speed over 3 and the whole AC system shuts off. The only way to get it to work is to shut it off and on again with the fan speed on 1 or 2.
Dealer has been asked by MG to find out the software versions on ecu, etc., but they haven't been able to fit me in yet.
If you are in eco mode it shuts certain things down so that you get more miles per kwh.
 
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