VP Air Con cutting out

VP-Matty · #1 23-12-2007, 10:09 AM

Hi guys,

I have had my Air Con reconditioned about 2 years ago and got a regas and new drier, etc.

However what I am noticing now is that my Air Con rarely works. I'll turn it on and hear my revs drop but no cold air comes through the vents. Every now and then it'll work fine for a few minutes but then it will stop.

I'm not all that technically minded, but I was wondering if it might be a relay or something as it to me sounds electrically related. I have checked the fuse and it is OK. Is there another relay or something that might need inspection?

Any help would be greatly appreciated. Thanks in advance for any info offered.

Cheers,
Matty.

accentstencil · #2 23-12-2007, 07:59 PM

It may have a slow leak and there isn't enough refrigerant for it to work properly. I would have it checked for leaks and a re-gas if necessary.

ivaninoz · #3 23-12-2007, 08:17 PM

Matty,
Did you use it during Winter?
Not using it often speeds up its demise.

VP-Matty · #4 24-12-2007, 09:45 AM

Hi accentstencil and ivaninoz,

Thanks so much for your replies.

4 years ago I had it regassed and UV dye was added. 2 years ago the guy said there was no sign of a leak and that the drier needed replacing.

Yes, the air con has been used over winter, but my VP is my second car and hasn't really been used that much I spose.

I got under the bonnet this morning and had a bit of a play around. It may have something to do with the connections on the back of the drier (or at least I think it's the drier - dog food can size cylinder nearest the passenger windscreen). If I wiggle the two spade connectors it seems to cut in and out. I have pulled off the connectors and both look clean and both were firm to remove. I therefore think that there is enough connectivity through those contacts.

Can anyone tell me what this connection point is and if there is any way to get the air con working - even temporarily? I am assuming this screwed in fitting needs an auto-lecco to replace?

Thanks again for any assistance.

Cheers,
Matty.

commsirac · #5 26-12-2007, 09:01 AM

Not sure where exactly the receiver dryer is on a VP, assume you are talking about it.....and not the compressor which will have a drive belt going to it.

Given we are talking about the dryer, the terminals you are wiggling are probably the low/high pressure switch. It stops the system from working if the majority of the gas has leaked out(low pressure) and as a safety feature for high pressure to stop hoses bursting, other parts fracturing..

It may be that your switch is playing up, or that you have got slightly low pressure in the system which is just on the threshold for low rating of the switch. You can take your chances and bypass(join the wire in and out) the switch to see what happens, if it cools well then you have most likely got enough gas there......and all will be well......except you will be running around without the protection of this switch.
You cant install another switch without evacuating the system, best option is to take it to an ac mechanic and have the pressure of the system checked and the appropriate fix put in place.

PRH · #6 26-12-2007, 02:39 PM

G'day Matty
Wot you are talkin about is the reciever drier, the switch is a low pressure switch you can bypass it (for test purposes only !!!!!!!!!!!) coz ya can kill ya AC comp if its out of gas,i have seen these switches fail.
Some of them can be changed without regassing the system as they have a Schraeder valve fitted to the drier body,i would take it to a qualified person to check this.
When it fails does the fan still blow air ?
Regards Phillip

VP-Matty · #7 27-12-2007, 09:46 AM

Hi commsirac and PRH,

Thanks so much for the replies.

PRH, yes the fan still blows air all the time. When I wiggle the wires on the back of the receiver drier, the compressor (I assume) kicks in and the revs drop and my girl reports that plenty of cold air comes through the vents in the cab. When I let go of the wires the compressor kicks out that's the end of the cold air.

I am assuming for the info above that the low pressure switch is suspect, as I can't see (in my unqualified opinion) how wiggling the terminals could affect the pressure inside the system.

I'll take it to an auto lecco and see how it goes.

Thanks so much for all the advice.

Cheers,
Matty.

PRH · #8 27-12-2007, 10:47 AM

Are the terminals on the actual switch loose ? the other thing it may be is that the wires are broken right at the terminal, take the terminals off the switch and see if ya can pull them off the wires,worth a try might save ya some $
Phillip

VP-Matty · #9 09-01-2008, 03:25 PM

Hi PRH,

Thanks for your reply.

The wires are fairly tight, so I don't think that a wire is broken as such.

As to your comment about the Schraeder Valves - would you know just by looking at the drier body whether it would have such a valve fitted? A can take a photo and up it if that might help...?

Cheers,
Matty.

VP-Matty · #10 21-06-2008, 09:18 AM

Hey all,

Just in case anyone else is experiencing the same problem I thought I should give an update.

6 months later I finally got around to taking her to an Auto Electrician. As commsirac suggested above, this problem was the press switch. $45 later the air con is working brilliantly!

Thanks!

Cheers,
Matty