Air Con: All Air Con Lights are on, but clutch doesn't engage

[theseriojca]

Hiya

new XC90 owner here, bought a 2010 D5 Lux Premium, automatic, a few months ago. I have bought it off a private seller for a very reasonable price, but there were a few caveats. I've managed to sort the handbrake (installed the adjuster, new disks and pads etc) and the extra oil but this last big thing I just can't get my head around.

The Air Con has not been working for who knows how long - I've taken it to ATS Euromaster here in Glasgow for a recharge, they ran the cycle and said the machine put in exactly the amount it took out and didn't charge me for it (brownie points to ATS).

After that, took it to our big Glasgow Volvo indy for an MOT and a service and asked them to have a look at it as well. They've recharged the refrigerant (and charged 50 quid for it!) and said they don't know what it could be, but they suspect it's the Evaporator Temperature Sensor. Having looked into that, it seems to be a many hours job which involves taking apart the whole dash and cost a fortune.

I've done a bit of googling and reading around here and checked the clutch gap. It's about 0.75mm, which is more than the spec so might be that, although I've tapped the clutch when running and it didn't seem to want to engage at all.

Following that, I've disconnected the white connector that runs to the clutch/compressor to see if it's getting any power and the multimeter only showed 0.02V either way - so there's no power coming to the clutch to tell it to engage!

Any ideas what could cause that? The Air Con light and the Rear AC light come on when pressed, there's no fluff at the temperature sensor and there are no apparent leaks (or so I was told).

Any input greatly appreciated, thanks in advance, I took a few pics to show the connector (just in case it's not it).

Ta,

Serge

Connector

[gmonag]

You are halfway there...

It seems to be a power issue to the compressor, so follow the wiring. You have checked the fuses/relays?...

Engine Compartment
Relay FMI2
Fuse 11

I think

[theseriojca]

Hi Greg, thanks a lot for your advice, here's my findings:

Just checked the fuse (all good - actually swapped it for a new one, just in case, then swapped back), then checked the relay with a multimeter and a 9V battery - all working.

Plugged them back in, no change.

Decided to experiment:
1. engine running, AC on - pull the relay out =>fan started going mad.
2. engine running, AC on - pull the fuse out => revs go up to 1600 and stay there (got a bit of a fright here, as after plugging it back in it wouldn't go down, turned the engine off and quickly back on - still at 1600 RPM, shut the engine for a few minutes and then it came back to normal).

Any other ideas what could it be? Don't have a helper to press the AC button and for me to listen to the relay just now, not even sure if I'll be able to hear it anyways, but I'll try later with the Mrs.

On a side note, the back of the fuse panel says there should be a vacuum pump relay at MI1 - I don't have one, is that ok?

Cheers,

Serge

[cheshired5]

A faulty pressure sensor, evaporator temperature sensor, ac pressure sensor etc. could all prevent the ac from engaging.
Dice and Vida are definitely your friend in this kind of situation as so much live information including the gas pressure the system thinks it has is available and you can remotely activate switches too.

Cheaper than paying for bad guesses and unnecessary work from "professionals" too.

[theseriojca]

Thanks, Cheshired5, I guess that means taking it to the garage then?

Even if I do get VIDA and it does tell me it's a sensor somewhere, I would still need to get it evacuated/dismantled/refilled and the such. It would need to be the Volvo independent one as well, not an aircon place (doubt they have VIDA), you think?

Thanks,

Serge

[cheshired5]

Pretty sure that all temperature and pressure sensors can be replaced without gas evacuation.
Vida isn't absolutely essential for data but a scan tool that can interrogate climate modules is.

Obviously, I sell Dice and Vida setups but perhaps a local member with Vida could read your car?

[theseriojca]

Hi Cheshired5

I tried to PM you, but not allowed yet apparently. Would you mind getting in touch with me, please?

Thanks,

Serge

[theseriojca]

Resurrecting the thread

Had the car read with VIDA, came back with CCM-0003 Evaporator Temperature Sensor Signal too low.

Guess that means that the Evaporator Sensor needs replaced, but after lots of googling I could only find that on Left Hand Drive cars that's a piece of cake procedure which involves removing some trim around the CCM whereas on RHD cars it involves removing the whole dash and the CCM itself (as per VIDA as well).

Anyone have to go through this procedure before? I would guess it'd cost a pretty penny for all that labour - is there any other ways around the issue? I did find a report on a different model when a hole was made in the pipe with a soldering iron and the original sensor wires cut and all that, but even that involves removing the dash!

Any help appreciated, thanks in advance!

Serge