Aircon problem, control valve ???

[carrera]

It's that time of year again, for a few days anyway

The aircon was working fine until the head gasket failed. Upon reassembly I initially forgot to connect the electrical connection for the control valve


My understanding of the control valve is that it replaces a mechanical on / off clutch, instead allowing a varying amount of refrigerant to pass through the valve to the compressor. The varying amount is achieved by a PWM voltage which opens / closes the orifice. I belive the PWM is provided on the earth side 

I have DTC B393B 04, which indicates that a voltage is being sent, but no current is being drawn 

i have carried out basic electrical tests. 

Ignition on there is 12.5v on the feed side, so I presume the PWM starts at 100%, with the earth "on" switch being a simple switch within the K33 HVAC module

The remainder of the WIS diagnostic instructions refer to chacking the K33 control module and the connectors, which are buried within the centre console. Seems like a good diagnostic approach, but I haven't been in there and I confirmed there is no short between +ve and -ve on the K33 enit by checking for continuity at the control valve connector

So the obvious thing to do was to provide power from an external battery to the control valve, expecting to hear a click, some movement, or even a little arc when completing the circuit. Inspiration here.

Nothing. So I think the valve has failed

What to replace it with. Aircon seems to be a huge mass of constantly changing numbers. I though I had got lucky when I found a compressor from a 160HP DTH engine. Looking in WIS, the compressors are different part numbers from each other, and more importantly, what is in WIS is not what is on the car, or the used part.

What is common is that it's a Sanden PXE16 compressor. Instead of being a 1608P, it's a 1605P, and the GM part number ends in 07



 
I haven't found anywhere to get a cross reference for a new control valve, so am thinking of getting the used compressor and swapping over the control valve as I suspect the control valve is a common component, with different electrical connectors for different manufacturers

Any thoughts or suggestions

[sgould]

I've not used them - yet.

There's a specialist aircon company down this way that only does aircon/refrigeration.  They are well recommended locally, even though their premises look disorganised.  They may have spare parts etc. or some advice.

https://www.vanchilla.co.uk