Weird problem with air con

[coops10]

Ok so I tried to turn the air con on last night which I very rarely use, if ever. I press the button, the snowflake appears but as soon as I let go of the button it disappears ! So basically it wont stay on.

Around 20mins later I notice the engine management light has appeared on the dash. Car seems to be running fine, no misfire etc.

Would the air con problem be likely to be the cause of the ecu light to come on?

Any idea what would cause this ?

Anyone near the HA4 postcode that has a fault code reader that could spare 15mins to help me out ?

Thanks.

 

[Ronin225]

Air con will only kick in at over 2 degrees
EML maybe unrelated

 

[coops10]

That would make sense, it was negative temperatures last night.

Just hope the EML light is no biggie, insurance and MOT at the end of the month

 

[coops10]

Hopefully it will be above 2deg today so I can check it out.

Anyone in or near Middlesex that could help me out with reading the fault code ?

Thanks.

 

[Andrewcupra TDI]

if you hold the aircone button in you supposidly over ride it , but once let go it disappears

but as said below a certain temp it wont work

the mrs's megan works in any temp and hasnt blown up yet so cant see why its a safety thing

mines seems to work above 1 degrees up

 

[Dajmin]

Maybe they just don't want you getting a cold, sitting in freezing temperatures with the A/C on

 

[coops10]

The only reason I wanted to turn it on was to see if it would warm me up quicker, no chance of that lol!!

 

[Muttley]

You do understand that the "snowflake" symbol indicates that the air cooling compressor is in operation, don't you? I can't contrive of any way to make that warm you up quicker . . .

 

[welsh frtdi]

sound s lto like you possibly have a faulty compressor switch(possibly if it dont work when temp is up over2'c)the switch recocnises gas pressure when you engage the button ie it sends a current to the compressor cluth to engage the pulley if you look at the front of your air con compressor when air con is off the front part of compressor should not be turning as the clutch is disengaged. try listening for a click from compressor when air con is engaged. the switch sometimes causes a fault linked to the ecu when low gas content is detected. if theres no click when you engage the air con test the switch or give it a live(12v) this is only a possibility.dont try that unless you well sure of what your doing.

 

[coops10]

You do understand that the "snowflake" symbol indicates that the air cooling compressor is in operation, don't you? I can't contrive of any way to make that warm you up quicker . . .

At the time I was too cold to think of this lol

sound s lto like you possibly have a faulty compressor switch(possibly if it dont work when temp is up over2'c)the switch recocnises gas pressure when you engage the button ie it sends a current to the compressor cluth to engage the pulley if you look at the front of your air con compressor when air con is off the front part of compressor should not be turning as the clutch is disengaged. try listening for a click from compressor when air con is engaged. the switch sometimes causes a fault linked to the ecu when low gas content is detected. if theres no click when you engage the air con test the switch or give it a live(12v) this is only a possibility.dont try that unless you well sure of what your doing.

Ill wait until it gets warmer and give it another try, was 1.0deg all day today

 

[Muttley]

The air cooling compressor will not engage if the outside air temperature is 4°C or less. The best explanation I've come across is that this prevents ice formation on the cooling matrix which would block the cabin air intake.

Cabin air comes in via the pollen filter and then hits the fan. After this is the air cooling matrix, across the full duct so all the incoming air is cooled. Then the duct splits, one half to the heater matrix, one half straight through. The desired cabin air temperature is achieved by mixing the two.

In the summer, air cooling will cause moisture to condense out - cold air can't hold as much moisture as warm air. Heating it up again drys it out.

When the outside air is very cold it can't hold much moisture anyway, and there would be very little drying effect gained from trying to cool it further.

 

[godber225r]

This bloke is right listen to him

 

[coops10]

I have

Ill try it again when it warms up and will see what happens, wont be for a while though! Bloody snow lol

 

[Muttley]

Here's a diagram of the ventilation system, to make it a bit clearer.

 

[Muttley]

Well, as we have warmed up a bit today I tried running with the air cooling on at an outside temperature reading of 2°C, and the snowflake symbol stayed on indicating that the compressor was running. So despite what some of the books say, it's 2°C or less where the air cooling shuts off.

 

[coops10]

Yep, can confirm it works fine now that its warmed up a bit, but the ECU light is still on

Anyone nearby with a fault code reader ?