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[vrba]

Does anyone know for what is this little thing mounted on the AC pipe.
It’s on the bottom of the car you can see it when you look from beneath, the jack that comes in has 4 pins and I think that this is the main reason for my vents freaking out cause today I see that all cowered in green thing from AC cause somewhere is a leak so I start to clean the jack and few times I plug and unplug the jack vents ware all fine (after 6 months) so I thought finally I found what was wrong, started the car vents all not working (OK) temp raised to 97 fans kicked in BUT they stuck (working) again [ch61516]. So now I think that the problem is in that little silver thingy.

so when the jack is off vents are not working so this has something to do with them

Sorry for bad picture I didn’t have camera when I was working

[feeutfo]

a camera phone any good? need more info, i think ? sorry

[vrba]

tomorrow than

[vrba]

This thing in the middle with wires on it, what is it purpose, what this does?

[TheBoy]

Looks like a/c pressure switch  :-/

[vrba]

what happens if that is out of order?

[Big_Mart]

If the pressure switch don`t work the a/c compressor won`t cut in.

[vrba]

ok, but can this effect my vents working and cause they are stuck and they work all the time. as i wrote above when i was messing and with that switch and cleaning it all the sudden vents fix them self. but they are stuck again and now my a/c wont work. i have a gas leak so i was thinking that there is not enough gas in system and that that is the problem for ac not working

[TheBoy]

lack of gas will disable compressor.

Entirely unrelated to your vent problem.

[feeutfo]

evening all, arent the vents vacume operated?

[vrba]

but the strangest was when vents fix them self when i was messing with the jack.

that's why i ask questions about this part and does it have some connection with all the vents

[Big_Roger]

Hi Stjepan,

First, so that everyone understands what you are trying to describe, you need to refer to your "vents" as fans, and the "jack" as a plug. In the case of what you are describing, it is actually a free socket, but we still call it a plug.  English is not a logical language!!!  I think your English is very good.

We do have ventilators, which can be fans, but to we English, the vent in this context generally means the slots where the air comes out to blow into the car or up to the windscreen. We also have jack plugs, but these are generally for audio units or low voltage power supplies.

A jack is what we lift our cars up with.

Now to your problem.

The item you are asking about is the high pressure switch for the air conditioning refrigerant compressor.

It is a two stage pressure switch.  As the pressure rises in the high pressure output from the compressor, if the pressure rises too high because the refrigerant is getting too hot, because maybe the cooling for the condenser is not enough with the fans on half speed, it switches them to high speed. (They will already be running half speed if the air con is switched on)

If then, the pressure continues to rise, even after the fans are on full speed, then the next stage switch interrupts the feed to the magnetic clutch, and switches off the compressor.

So to answer your question, yes, if this pressure switch was faulty, it could affect the operation of the condenser fans, as could anything wrong in the plug or wiring connecting to it.  Also, if it has gone completely wrong inside it, and has jammed in the fully operated position for both switches, then the compressor would not run because it would wrongly detect too high a pressure in the system and switch off the clutch.

The fact that your previous meddling around with the plug into this unit fixed the problem for a while points to something wrong in this area.

To change this switch, you will lose any gas in the system, and need to have evac and gas re charge. Do not take out the switch untill you have the replacement to fit immediately. Do not leave the system open to air.

For information, there is also a separate low pressure switch in the system to detect loss of refrigerant.

HTH

Roger

[Turk]

Good post there Big R. Very informative.    
Something to bare in mind, especially if your foolhardy enough to use one of the DIY re-charge kits on the market, any person found guilty of knowingly releasing controlled refrigerant to the atmosphere is liable to a fine of something like £30,000.    

[feeutfo]

30k  nice one roger,  

[vrba]

roger thx for the corrections, as you all can see i'm from croatia and some things about car i don't know to say it in eng. correctly  :-/ but i'm trying .
hope now everybody understands what i'm talking about  

my system was opened to air for some 6 months or so, when the car was at mechanic, is that a big error or what.

what can be if the system was opened to air for that long after that i just refilled the system  

thx again