Focus 2006 AC

"Pressure is OK" makes me shudder a little... You must be referring to static pressure.. the gauge reading is PSI at degrees F.... Do you have power to the low pressure cut out switch (sometimes called the clutch cycling switch)?

Hi,

Our 2003 ZX2 had the AC just stop working, took it to dealer and they replaced some kind of controller for the AC, about $350 for the part as I remember, it was listed as a typical problem with the car. Maybe your problem too.

Here is what I found googling it.

The general cause of the no/intermittent AC operation is the failure of the circuit that engages the AC compressor clutch. This clutch is electrically operated. The specific problem is the failure of a relay inside a small electronic module that is mounted in the engine compartment under the air filter housing. The module is called the Contant Control Relay Module (CCRM). The CCRM is essentially a metal housing with a single circuit board inside that has several relays on it. One relay, what Ford calls the 'WAC' relay developes a poor or broken connection (solder joint) to the circuit board causing the AC clutch energization circuit to become intermittent or fail completely. The WAC relay controls the operation of the AC compressor clutch. Ultimately the WAC relay and the entire CCRM is controlled by the main vehicle computer or Powertrain Control Module (PCM). The reason Ford uses this somewhat complex route to control the AC is it allows the PCM to sense the AC load and adjust idle and other engine parameters. It also allow the PCM to coordinate the operation of the engine electic cooling fan(s) in conjustion with AC and other load situations.

More follows:

To correct this problem you can:

1. Replace the CCRM. A new CCRM will cost about 0 - 0 depending on where you buy it. It is a fairly easy part to remove and install.
2. Repair the CCRM. If you have basic automotive, mechanical, and electronics soldering skills you can remove and disassemble the CCRM, and repair the failed solder joint. This repair will cost 1. Replace the CCRM. A new CCRM will cost about $200 - $300 depending on where you buy it. It is a fairly easy part to remove and install. 2. Repair the CCRM. If you have basic automotive, mechanical, and electronics soldering skills you can remove and disassemble the CCRM, and repair the failed solder joint. This repair will cost $0 but assumes the mentioned skills and will require a drill/bits (a drillpress works even better) and an electronics type solding iron. Depending on skill the entire repair takes about an hour. but assumes the mentioned skills and will require a drill/bits (a drillpress works even better) and an electronics type solding iron. Depending on skill the entire repair takes about an hour.

I'm an ac engineer, by that I meant that I just connected a low side gauge, and reading pressure as a temperature, it was about 17C, which should be ok to energise the system.

Thanks for all that, very helpful, I'm ok with electronics so I may well take a look at this.

Well, then...

Do you have power to the clutch cycling switch? If you bypass the switch, does the compressor clutch engage?

The pressure switch on the low side is closed, I didn't check to see if there was current flowing at the connector, I'll check that.

Thanks.