AC won’t stay on?

[anxious_ant]

Car was fogging up today and I noticed the AC is not on. I tried to manually force it on but it won’t stay on.
If I stop and restart car the AC light comes on but goes out after few seconds. Is my AC broken or is this normal behaviour when it’s cold outside? (Ambient temp 1C).

Car is an Audi.

[Coatesy351]

If it's low/out of gas the compressor usually won't kick in. I think it's to save it from damage. Maybe a regas with the UV dye so if it is leaking it can be traced.

[milu]

Below 5 degrees usually means no AC

[S100HP]

Aircon does not work below a certain temperature.

[E-bmw]

Air outlet temp of A/C is normally 6 deg C, most A/C systems these days are actually Climate Control, which a bit more clever, so below 6 deg C it isn't required as above, so what will happen is it will come on, check the temp & go off.

[anxious_ant]

Thanks for the replies all. My thoughts are the same, ambient temperature too low hence AC won't kick in to avoid damage.
In regards to the fogging I suppose in today's scenario it's exceptional as the whole family is pretty soaked before getting into the car causing the condensation.

edit: thought I should've mention car in question is 2010 Audi Q7.

[anxious_ant]

Ambient temperature yesterday was about 10C and the AC still won't come on. Even at the lowest setting without triggering max fan the air doesn't feel cold.
Booked by car in for a regas, hopefully that's it and not a leak or something more sinister...

[DuraAce]

If you need a regas then you've lost gas somewhere over time. I know you can get very slight loss over long periods but I suspect you have a fault.
If you're low on gas (or empty) they should leak check using nitrogen first. If no immediate leak then they should be adding uv dye to the gas to assist with future leak detection.

[anxious_ant]

DuraAce said:

If you need a regas then you've lost gas somewhere over time. I know you can get very slight loss over long periods but I suspect you have a fault.
If you're low on gas (or empty) they should leak check using nitrogen first. If no immediate leak then they should be adding uv dye to the gas to assist with future leak detection.

Had a chat with local specialist and they mentioned that the regas machine would detect leaks as well.
However he also said the pipes in Q7 are very susceptible to leaks and its over £500 to repair if so... Merry Christmas to me

[thetrickcyclist]

anxious_ant said:

Had a chat with local specialist and they mentioned that the regas machine would detect leaks as well.
However he also said the pipes in Q7 are very susceptible to leaks and its over £500 to repair if so... Merry Christmas to me

Get a mobile a.c. specialist to look at car before going to a garage...

[anxious_ant]

thetrickcyclist said:

Get a mobile a.c. specialist to look at car before going to a garage...

Didn't realise there is such thing as a mobile AC Specialist... Booked into the local garage tomorrow anyway so I'm really hoping it's not a leak...

[anxious_ant]

Gas was showing 10g when plugged in and that's well below the 200g minimum. Topped up now at 700g and machine didn't detect any serious leaks.
This is first AC top up in 8 years so fingers crossed no serious leaks.
I will have it inspected again next MOT in summer.

[Penelope Stopit]

This was a nice cheap fix for you, sometimes the compressor seal leaks but doesn't always show as leaking at the time of service