I did originally post this in the General Car discussion but got no replies o here I go again with more, updated information.

I have a MK2 1.4 2006 LX where the air conditioning is not working.

I have continuity-checked all the wiring between the PCM, the engine bay fusebox and each individual switch or component and it all checks out.

The compressor clutch works if the compressor cutch relay (WOT relay) is manually activated

The PCM has been changed and then reprogrammed with the latest level map.

Aircon charge is correct at 600g with appropriate PAG oil.

High and low pressure switches have been swapped out.

When pressing the aircon switch in the car, the switch lights up and live data on diagnostics shows switch activation so at least one control module is seeing activation (not sure which one).

Short of changing the GEM module I am running out of ideas.

Can anyone help?

 

Have you tried a gem self test to see if the gem is recognizing the switch on/off?

I've not tried this myself and not sure if it's possible. From the op it seems that even though the GEM is being switched, that the relay isn't

 

I have IDS so will do that this evening but I think that it does as I seem to recall something when doing some other checks prior.

i have +4.5v from pin 9 (if I remember correctly) to pin 2 of the aircon relay instead of -ve so May have to depin the PCM and run a test lead to disprove a short in the wiring loom as well.

 

It's not unusual to use negative and or positive switching in controls.
The A/C control PCM output may be negative and the 4.5.v you see is 12v in series with the relay coil.

Given what you've tested it's quite likley the PCM is seeing an actual or a false hold off signal.
I know Wide open throtlle usually disables A/C there must be others.

 

Bit of an update on this...

with the wire from the PCM to the WOT relay disconnected, there is +4.5v out of the PCM (as per FocusV8 theory).

The system has been regassed after finding a suspect pipe from the compressor to the condenser so that is all good.

ForScan and IDS both show that the heater control module (heater panel) is sending a signal to the GEM module and the GEM module is receiving this signal. The PCM is showing as no signal being processed so is either not receiving the signal from the GEM or is seeing some problem which is stopping the activation.

There are no DTC for any of the modules, including the instrument cluster which apparently converts the various CAN signals between the modules.

 

it could be the shims in the clutch pack have worn out

or it could be the orrifice tube thats blocked that needs replacing, the mondeo in general has a similar issue with this and i'm not sure if it comes seperatly or with the pipe

on the mondeo it's in the pipe on the bulkhead