Air conditioning question

[shaun5]

Now the cold/wet weather is here i use the air con to try and demist the inside of the car. On a recent trip the air con wouldnt work (it was to cold) i found out that at 7-8 degrees it started to work again, not much use as the temperatues sometimes dont get that high in the winter. Has anyone else experinced this?

The sensor for the external temp gauge is situated at the front of the car, is this used to gauge temperature to stop the air con working?? My mates car has got air con (not working) but no temp display (its an early car "h" reg) so im thinking not.

Is there any way i can make the air con work at lower temperatures? its brilliant at demisting.

[Skull]

dont do it, running the aircon at low them can damage aircon parts. it is not like this for no reason.

[shaun5]

Ok, if thats the case i wont do anything, just wondered!! out of interest why shouldnt it be run when cold? Will it ice up to much?

[johne]

Ok, if thats the case i wont do anything, just wondered!! out of interest why shouldnt it be run when cold? Will it ice up to much?

The reason for the temperature limit is that if you let air in too close to freezing the moisture in it will freeze up on the evaporator. That won't actually hurt the air-con as is often stated but it will stop ALL air getting into your car which'll mean it'll steam up inside on the windscreen and you can't clear it because the heater is after the evaporator so there's no airflow and no easy way to defrost it except turn it off and wait.

The turn off temperature is monitored and controlled by a crude bi-metallic switch just under the pollen filter. It should work at 3 degrees but due to it's crude nature it can cut in much higher like 7 degrees as yours is.

Aircon is brilliant at keeping the screen clear so I like you want it to work as long as possible. There's nothing to stop you bridging the switch under the pollen filter so it never cuts out or trying a different one that actually works at 3 degrees, just be aware of your heater airflow starting to cease and turn the A/C off pronto before you loose all airflow. If you can switch to recirc mode before it freezes up completely then the heat drawn in from the car will defrost the evaporator pretty quickly and you can carry on. Of course you could just stay in recirc mode to stop the freezing.

John

[shaun5]

The turn off temperature is monitored and controlled by a crude bi-metallic switch just under the pollen filter. It should work at 3 degrees but due to it's crude nature it can cut in much higher like 7 degrees as yours is.

Cheers John

You learn something new everyday, i'll have to look at the switch and see if there is any obvious fault with it. I hardly use it in the winter but when i do i like to be able to see where im going

Anybody know how much a new one costs?

[A80Avant]

how is that temp sensor reached? i need to change mine to see if my A/C will ever work again!

[johne]

IIRC around £25. Someone on here may have one as many folks have removed their air-con.

John

[A80Avant]

i have the sensor, its whether i need to remove the interior shelf, or is it reachable from below the pollen filter?

[johne]

how is that temp sensor reached? i need to change mine to see if my A/C will ever work again!

The temp switch has an approx 30cm flying lead with a connector on the end. If you've got manual A/C I suggest you find that connector and put a temporary join across the pins if you want to test out your A/C. If you've got electronic climate A/C use a 1000 ohm resistor instead. The connector will be around the blower fan assembly so you should be able to get at it from the passenger footwell or behind the glovebox.

John

[A80Avant]

i see,
well is the sensor difficult to remove? rather than trying to buy a resistor for testing, as i already have the sensor, it is going to be easier to remove rather than test it. Might as well do it and if the AC doesnt click in, then i have eliminated that as a reason as well.

[johne]

There's more than one style of sensor and I've never removed one whilst the heater blower unit is still in the car but you can see it as soon as you remove the pollen filter and you should be able to push it into the car from there and then retrieve it from up behind the glovebox. Getting it back in again might be a bit more tricky

John

[A80Avant]

I see. I have the rs2 lhd specific sensor, so ill have to search in there and see how it mounts. More next year as the days are warmer!

sent using Android

[bobby singh]

Hi I know this is a old thread but Im experiencing no AC during these cold conditions but what is strange there is no power to pin 1 on the AC/REC plug. Is this normal? I was expecting the ac not to function via means of compressor clutch engagement not by cutting power to pin 1 to the switch.

[bobby singh]

Answered my own question by heating the sensor under the pollen filter and the AC (and REC) buttons powered up.
Might be useful for someone who fell into the same trap as me.