Air Conditioning

[Andrew_72]

Cheapo, you can easily check if it is the icing up issue. When the problem occurs, stop the car and lift the hood. Check to see if the aircon pipe leading into the firewall is covered in ice.

I've had the same issue. I'm guessing it's the evaporator temperature sensor that's gone. Same symptoms as you. After a while the air stops flowing through the vents. Manually switching off the AC gets the air flowing again after a few minutes as the ice thaws. You will notice that the new air that starts flowing is still cold from the ice even though the AC is off. The other tell-tale is lots of water under the car from the melting ice after the problem occurs.

Just can't seem to find the exact location of the sensor though (which is another story/post!).

[cheapo]

Cheapo, you can easily check if it is the icing up issue. When the problem occurs, stop the car and lift the hood. Check to see if the aircon pipe leading into the firewall is covered in ice.

I will do this, but wouldn't there almost always be ice on that pipe?

I've had the same issue. I'm guessing it's the evaporator temperature sensor that's gone. Same symptoms as you. After a while the air stops flowing through the vents. Manually switching off the AC gets the air flowing again after a few minutes as the ice thaws. You will notice that the new air that starts flowing is still cold from the ice even though the AC is off. The other tell-tale is lots of water under the car from the melting ice after the problem occurs.

Those are exactly my symptoms.

The dealer just called to say that they cannot find anything wrong with the AC. No error codes at all. There is an SRS warning on the DIM (Driver Information Module aka instrument cluster) and Vince, the technician, says it's possible the bad DIM is messing with the ECC. New DIM: $1500-$1600. Not going to do that. Sigh.

Any further pointers would be appreciated.

[Andrew_72]

I will do this, but wouldn't there almost always be ice on that pipe?

Nope. Shouldn't be.

[cheapo]

Did some driving this weekend and I pulled over once the AC stopped blowing to take some pictures.







Does this prove anything?

Again, the dealer and his computer found no error codes.

[stevepaa]

I have the same issue.
I had the refrigerant sucked out, and it was 1 lb low.
I took all the lines apart from expansion valve forward and I found one o-ring pinched/cut from the factory. I replaced all the o-rings.
I replaced the expansion valve and dryer.
I had it recharged and the problem persists.
I am replacing temperature sensor 30665118 tonight.

[cheapo]

Is that the evaporator temp. sensor or something else?

Please let me know how things turn out!

[stevepaa]

yes, the evaporator temperature sensor, really just a termocouple in a plastic case.

http://www.v70xc.com/forums/showthread.php?t=14631

[cheapo]

Are you going to remove the dash to make the replacement?

[Jerrymcc]

listen for the compressor cycling on and off. If you hear it cycling frequently, like every 5 sec, it means is low in refrigerant.

If you are mechanically inclined, you can recharge it yourself and add the refrigerant that has the leak dye in it.

If there is a leak in the system , then the uv goggles will spot the site of the leak next time.

Goggles alone won't spot it, they are to protect your eyes from UV...You need a UV source, like a black light flashlight...

[Jerrymcc]

Did some driving this weekend and I pulled over once the AC stopped blowing to take some pictures.







Does this prove anything?

Again, the dealer and his computer found no error codes.

The line that is icing up should not be icing up...It is the low pressure line returning refrigerant from the evaporator to the compressor...It means that the evaporator is flooding and the cooling cycle of the refrigerant is occuring AFTER the refrigerant has left the evaporator...The process of evaporation is what causes the cooling and it is supposed to occur in the evaporator, not after it...This indicates a bad expansion valve...The valve looks to be stuck open and is not metering the refrigerant...It should be allowing only a mist to enter the evaprorator, not a stream...The thinner line below the iced up line is the high pressure line carrying refrigerant into the expansion valve and evaporator...The condition shown in the photos indicates a problem with the basic refrigeration system, not with temperature sensors, etc...

A brief description of how the A/C system works can be read at www.aircondition.com...