156 GTA air con hassles

My car has once again suffered it's weird air con problem as we head into summer - despite regular use (of the car and the air con) over the winter.

Basically, the compressor does not engage at start up most of the time. Whatever you do with the "auto" or air con buttons makes no difference, there is no cold air. Weirdly, it usually works from a cold start - so for the first journey of the day - and usually does not from a hot start. When it fails to come on at start up, it almost never comes on later. When it comes on, it always works until the car is re-started. It is just over 3 years old and has suffered this same problem every summer Does anyone have any ideas? one main dealer had it for 3 days and never solved the issue, but the main dealer I've used most recently for servicing fixed it fast and said it was "an electrical connection behind the dash". I don't especially want a main dealer messing about with it for days now it is out of warranty, and I'm at a loss to work out why this seems to recurr every year

JWyatt
Mine wasn’t working till up to a month ago, that’s after having two new AC pipes fitted and a re-gassed last October. Never bothered using the AC during the winter months so I was unaware that it wasn't working. Went to use it, nothing! Compressor was on but no cold air, checked the manual before I went back to dealer and complained (didn’t want egg on my face) at the dealer, diagnostic showed that the system was out of sync, took them 10 minutes to fix, now its baltic with the AC on.
Not sure if this is going to be any help to you.

Interesting... I was wondering, since it's clearly electrical, if a simple ECU reset might help mine... I think if you disconnect the battery for 15 mins then reconnect, that does it...

Mine was overfilled when re-gassed after a broken pipe and initially worked (in the mornings say) however when the temperature increased through the day it cut out, presumably sensing high pressure from the pressure transducer. I vented some off and it's been fine since, fingers crossed.

Originally Posted by gtachris

Mine was overfilled when re-gassed after a broken pipe and initially worked (in the mornings say) however when the temperature increased through the day it cut out, presumably sensing high pressure from the pressure transducer. I vented some off and it's been fine since, fingers crossed.

Interesting... How do you do this and what is the correct pressure? I suppose if it used a schraeder valve somewhere, I could use a mountain-bike shock pump to to check the pressure...

I just vented some off from the low pressure pipe valve, pipes down the left hand side of engine by cam belt cover, don't know what the correct pressure should have been but just did it on a very hot day and let out a bit at a time until the compressor clutch stayed engaged. Low pressure should be the larger diameter pipe.

Well, I vented perhaps 3-5 seconds off the low pressure and a quick blip on the high pressure, checked the fans were coming on as needed, checked all the air con fuses, resent the ECU and then....

... nothing. Same as before it worked a little this morning from a cold start then nothing.

The car did drive like stink after I reset the ECU then took it for a blat, mind

Sorry to hear that mate I'm out of ideas really. Hope you get it sorted.