General Blower works but Air Conditioning doesn't

[wurz1974]

I seem to have a problem with my aircon (Ulysse 2003 2.0jtd) Blower works as it should. All vents work as they should and direct air to the desired place. But when I reduce temp to 14 and put aircon light on the air just isn't cold enough.

My first guess was that the unit needed gassing so I had a guy look at it today. He works with fridges and freezers primarily, not cars. So anyway he connected some equipment up to my aircon system and told me there was definitely enough gas in the system and this was not my problem. He reckoned something to do with the aircon just not kicking in - something electrical. Could he be wrong?

Anyone got any ideas?

 

[digger58]

Hi,
Check visually if the compressor is cutting in, you should also hear the engine note change and the idle speed increase. If this is not cutting in check the connections to the compressor and see if you are getting power to it.
Tony

 

[wurz1974]

I was listening earlier for a change in the engine sound but it didn't appear to change. Where is the compressor and is it easy to access?

 

[digger58]

bottom of engine under steering pump, hard enough to get at.

 

[cipher]

it maybe that the system has no gas in it.

There could be a slow leak somewhere. You also lose some thru natural wastage.

If in doubt, get it checked with a UV Dye, or get it gassed with Nitrogen, this will indicate any leaks.

If the gas is low, then the low pressure switch will prevent the compressor cutting in, you can short the low pressure safety switch terminals to bypass and see if the compressor cuts in. Beware when doing this, as a low pressure not only means no refridgerant, but it also means no oil for the compressor.

 

[Mace]

it maybe that the system has no gas in it.

There could be a slow leak somewhere. You also lose some thru natural wastage.

If in doubt, get it checked with a UV Dye, or get it gassed with Nitrogen, this will indicate any leaks.

If the gas is low, then the low pressure switch will prevent the compressor cutting in, you can short the low pressure safety switch terminals to bypass and see if the compressor cuts in. Beware when doing this, as a low pressure not only means no refridgerant, but it also means no oil for the compressor.

Hi, exactly what Cipher says . I had the same thing, your system needs maintenance and refilling (my buddy's the expert, but I think it was a mixture of R407 and oil). Although Cipher sounds like he knows what he's saying, with respect, I do not recommend bypassing the compressor, it's expensive, you never know. UV dye or nitrogen will probably show the problem. Good luck (I recommend using a specialized car AC maintenance firm, I had some trouble with my local Fiat dealer not finding the leak).

 

[wurz1974]

I had a guy check it for gas and he said there was plenty in there. But he didn't use UV dye or anything else. He just connected up a gas bottle with some dials but said the system was full already and that he believed the problem was not gas but something else on the car. I'll need to get someone who actually works with vehicle AC to have a look.

 

[Mace]

Sounds like the compressor is not receiving a signal or busted. Specialized job, good idea to look up someone who works on car ac's all the time. (B.t.w. the refrigerant in a car is R134a, not R407). Keep us posted what it turns out to be.

 

[Mace]

hi,
did you find out what it was?

 

[paul 2407]

it will probably be the air con pressure switch located on the top of the receiver drier when this fails it stops telling the compressor to kick in beware though you will need to drain the system first otherwise you will just lose all the gas in there.

 

[wurz1974]

I was getting some work done a few weeks back and I had my mechanic check the compressor just to rule that out. He was able to confirm that it seems to be working as it should so maybe it's the gas afterall. With the really poor summer that we've just had I hadn't really needed the air-con so it hasn't really been a priority but I guess that when I do get around to it I'll take it to a proper air-con guy and let you know the result.