Took the opportunity to change the oil and sort a few other problems out this afternoon but found that the aircon was not blowing cold, even when set to 'LO' setting.  I checked the compressor and found that it was not engaging whatever the inside temperature was set for.

My first thought was that the compressor had failed.  To test this I took off the dust cover and exposed relay K60 to check voltages at each pin.  All test were done with the engine running.  With ECO mode on I got 14.2v at each pin except the line to the compressor clutch where I got 0v.  With ECO off and temperature set to 'LO' I found 13.8v at each pin and 0v again on the compressor clutch line.  When I manually closed the relay with a screwdriver, no matter what the temperature set in the car, the cooling fans come on and the clutch engaged.

I'm no electrician but should the relay be switching in both tests if there is 12v across the relay input?  Even so, does anybody have any idea why why the compressor isn't engaging?

most likely not enough refigerant in it!!

I'm sure you are right!

I just want to be sure I haven't got any electrical/compressor problems before I spend £70 (?) getting it tested and regassed

Go for the pressure switch then, but don't run for more than a few seconds ;)

Sounds like coolant is low and will require a recharge to correct volume as compressor will not run at low level.

If not replaced coolant or several years or unknown in your ownership worth getting it recharged as will work more efficiently anyway imho.

To test whether the compressor clutch is seized or not, pull elec connector off compressor, note polarity, and put 12volt across terminals - if clutch ok you will hear it engage with a loudish clunk.

The clutch does engage (as do the cooling fans) when I manually close the compressor relay.  I'm not sure, however, why the compressor relay isn't closing automatically as it appears to have 12v supplied on the input leg.

If the refridgerant is low it will not switch the relay to engage the clutch, regas and all will be good, unless you have a leak someware. that will show up if you have it vac and gassed.. :y

Does anybody know of a decent aircon gassing/leak check service in the Nottingham area?

Try Kwik Fit, they used to charge £40 to regass your car, if they didn't make it colder than so many degress of when you arrived you get your money back :y

..on a possibly very similar subject - this weekend my air con/heating/fan has completely stopped working. I get the full dash display for both zones, temperature digits display, fan speed indicators, auto,econ, recirculate - the whole 9 yards  :y - BUT absolutely zip out of the vents - no fan - even in eco mode  :-[. Doesn't sound like anything is trying to work. Could this be gas level too - or is there a fuse/relay fuberred somewhere  :-/
I can't see any one fuse that wouldn't affect something else - and all is fine as far as I can tell.

Cheers
Ian.

ianu wrote on 29. Mar 2011 at 20:15:

..on a possibly very similar subject - this weekend my air con/heating/fan has completely stopped working. I get the full dash display for both zones, temperature digits display, fan speed indicators, auto,econ, recirculate - the whole 9 yards  :y - BUT absolutely zip out of the vents - no fan - even in eco mode  :-[. Doesn't sound like anything is trying to work. Could this be gas level too - or is there a fuse/relay fuberred somewhere  :-/ I can't see any one fuse that wouldn't affect something else - and all is fine as far as I can tell. Cheers Ian.

If everything appears to work, but just no fan, first check Fuse 33, if thats OK I'd be suspicious of the fan or the speed controller

TheBoy wrote on 30. Mar 2011 at 10:11:

ianu wrote on 29. Mar 2011 at 20:15: ..on a possibly very similar subject - this weekend my air con/heating/fan has completely stopped working. I get the full dash display for both zones, temperature digits display, fan speed indicators, auto,econ, recirculate - the whole 9 yards  :y - BUT absolutely zip out of the vents - no fan - even in eco mode  :-[. Doesn't sound like anything is trying to work. Could this be gas level too - or is there a fuse/relay fuberred somewhere  :-/ I can't see any one fuse that wouldn't affect something else - and all is fine as far as I can tell. Cheers Ian. If everything appears to work, but just no fan, first check Fuse 33, if thats OK I'd be suspicious of the fan or the speed controller

Thanks TB - all fuses OK. Is the speed controller co-located with the fan ? I've just read Wellung666 guide on removing the fan  :o - - is there anyway of checking this without having to take it all apart first ?
Would a low gas level just inhibit the air con pump - because even in Eco mode nothing is happening with the fan. I can hear all the servo motors whirring away behind the vents - all the digital displays are working.
SO - just thinking out loud - should I be able to get the air con pump to trip in and out just by adjusting the temperature controls in the car between 'Lo' & 'Hi' irrespective of the fan working or not ? If so gas is fine ? and I'm back to the fan or speed controller ?  :-/

A quick 10 mins on a tech2 might be worthwhile before condemming the speed controller.

Scuttle drain ever been blocked?

TheBoy wrote on 30. Mar 2011 at 21:34:

Scuttle drain ever been blocked?

..not as far as I know TB - pretty clean when I got the car.
How you fixed for 10 mins on a TechII one evening over the next week(ish) TB ? pretty please

ianu wrote on 30. Mar 2011 at 21:51:

TheBoy wrote on 30. Mar 2011 at 21:34: Scuttle drain ever been blocked? ..not as far as I know TB - pretty clean when I got the car. How you fixed for 10 mins on a TechII one evening over the next week(ish) TB ? pretty please

Should be around, PM me when you know when, and I'll check with the boss...

I've had a couple of instances of my 2.6 fan refusing to run, the act of interrogating the ECC with Opcom restored it life on both occasions.

Slightly related question, does the coolant radiator really have to come out to remove the compressor?

Mike.