OT - Aircon help (cmax)
mcerd1 - 21/10/14 at 10:57 AM
I've had this car for nearly a year now and the aircon did work when I got it (in the middle of winter) but now I get nothing 
finally got change to start looking into the problem when I was changing the very squeaky belts at the weekend - this is the first car I've ever
worked on with aircon so any advice is welcome...
the button lights up when you turn it on but nothing happens
it looks like the clutch on the compressor is not engaging so obviously that could be the problem, but I believe these a low pressure cut-off switch
somewhere as well
I don't get any fault codes, but don't know if it would give a code or not
according to the sticker its been refilled in 2010 (no idea if that was the last time or not)
got the Haynes manual but its about as much help as chocolate fireguard
what else can I check / try ?
is it worth just getting it leek tested and refilled ?
cheers
-Robert
Mr Whippy - 21/10/14 at 11:09 AM
I'd have a look at the fuse first, their not much fun to work on, I have one and it's been nothing but bother
Just a thought they, the aircon in the cmax usually comes on automatically when the window demist is selected and is actually absorbing moisture when
it does that rather than cooling the car, indeed it's actually heating it up.
I think in that car the aircon will only start cooling if the heater control is set fully to cold so worth checking that first rather than just
pressing the button.
Agriv8 - 21/10/14 at 11:14 AM
I would For £50 refill inspection would be a start possibly local recommended garage rather that Quickfit.
Wifes parent bus Cmax 57 vintage 1.6Tdci has just jumped a Micro V grove and was squealing but was not a major job to move back to correct V. If it
does it again I need to look at bearing on tensioner that could be getting shot.
I also believe fords of this age are prone to the Sealing o rings drying out if Aircon not used they shrink and de - pressure the system
daft as it sound checked fusses wiring
ATB agriv8
[Edited on 21/10/14 by Agriv8]
mcerd1 - 21/10/14 at 11:26 AM
^^ it doesn't come on even with the temp set to the coldest setting
the belts hadn't slipped, just a bit worn and polished looking - it was actually the alternator belt that was making the noise of cold/wet days -
I only changed it because it was irritating
mine is also 57 plate (Jan 2008) - but with 1.8 duratec if that makes any odds
the compressor actually has a short belt all of its own with no tensioner (stretch belt) which I believe is more or less the same on all the
engines
the belt was running fine and still is with the new belt - but the clutch on the compressor is doing nothing as far as I can see
I've heard about o rings drying and I'm really hoping that's not the case
will check the fuse next - don't know why I didn't think of that...
(don't worry - I wouldn't go near quick-fit if you paid me to)
[Edited on 21/10/2014 by mcerd1]
Agriv8 - 21/10/14 at 11:58 AM
final word of wisdom from me for now.
IIRC ( can check if required ) there is tone change from engine and interior fan when A/C button is pressed.
ATB agriv8
DW100 - 21/10/14 at 12:36 PM
The most common reason is that the system is low on gas and therefore the system won't engage the pump clutch. The hose are slightly porous and
loose about 10% per year. At around 50% the system will stop working.
britishtrident - 21/10/14 at 01:20 PM
quote:
Originally posted by Agriv8
final word of wisdom from me for now.
IIRC ( can check if required ) there is tone change from engine and interior fan when A/C button is pressed.
ATB agriv8
Yes ideally get somebody to switch the AC on while you listen under the bonnet, you should here the AC clutch engage and engine sound change
slightly.
Also the heater blower must be on or the AC clutch won't engage.
The AC electric clutch works the same way as the clutch on some semi-automatic car transmissions of the early 1960s (such as the Smiths EasyDrive)
ie it is full of iron filings that have a big electromagnet round them, the filings lock into a solid mass when the magnet is supplied with 12v,
you can test the clutch by directly connecting the electromagnet to 12v from the battery.
If the clutch on the compressor is working then next stage after that is get the pressure on the low pressure side of the system checked when the
engine is running and AC turned on..
simonrh - 21/10/14 at 01:41 PM
My wife had a 2005 focus which presumably has a lot in common with on of these.
Something on the car's "control unit" went up the spout on the AC control end of things.
We had a new compressor and re-gas which worked initially but the CU was actually failing to turn on the auxiliary fan on the AC matrix which would
just lead to overheat and boiling off the refrigerant over time, especially on hot days in stationary traffic. Made some funny noises as it started to
run low and tried to clutch in and out continuously.
Apparently the auto electrics company who looked at it said the control unit was triggering the fan but no voltage was appearing at the fan itself.
Loom was OK. Suspect control unit and big bill or part-exchange. She now has a clio!
mcerd1 - 21/10/14 at 02:58 PM
quote:
Originally posted by simonrh
My wife had a 2005 focus which presumably has a lot in common with on of these.
^^ it'll be similar design, but not exactly the same...
mine has the slightly revised version of the electrics that's on the later / facelifted c-max and mk2 focus's - I found this out as the
fuse box layout is totally different yet the diagram in the manual was never updated 
ian locostzx9rc2 - 21/10/14 at 03:22 PM
Check it has gas in the system first before you get deeper into it.Aircon systems need to be run at least once or twice a month or the seals dry out
and you loose the gas from the joints.
[Edited on 21/10/14 by ian locostzx9rc2]
splitrivet - 21/10/14 at 03:51 PM
Usually low on gas, compressor shaft seals tend to leak if not run periodically.
If you think about it, its quite logical refrigerant gets warm in engine bay pressure builds up if it can find a way to atmosphere it will.
Cheers,
Bob