C30 AC low pressure switch part number confusion!

[VolvoRob38]

Hello again, onto the next problem solving mission.

C30 1.6d 2009

My AC compressor is not kicking in and with a little help from Cheshire5 on here testing for voltage and continuity narrowed the problem down to the low pressure switch. Recently confirmed by running diagnostics with dice and vida... and bridging the connector with wire the AC compressor kicks in and I get cold air. Also gas level was checked and is full with no leaks. So pretty confident the low pressure switch is the problem.

I ordered a new part from ebay (Germany) and when I received it I noticed it looked different and the part number was not the same. I tried it any way but it did not work.

So I contacted my local volvo garage and ordered the right part directly. Went today only to find it's the same part I ordered from ebay, the parts guy looked on his computer and said the old part number has been changed to this new upgraded part and number.

Old low pressure switch 30780427
New low pressure switch 31332642

I decided to try it anyway as the guy said I could get a refund if it didn't work, but hay ho what do you know... doesn't work. I am confused as the parts have different numbers and don't even look the same! (Photos attach)

(The bigger one is the old switch, with the yellow nipple inside).

Has anyone replaced their low pressure switch in a c30 and how does it compare to my new and old switches??

When I asked the volvo guy what is my next move he just shrugged his shoulders and said I need to speak to the technicians guy (2 desks along). So I did, and his only solution was to book it in for £50 so they could do a fresh diagnostic on it. I'm not paying £50 to be told what I already know or so they can change parts that don't need changing. I asked if there was a technical department I could phone but he said volvo only speak to technicians.

Thank God for volvoforums.org.uk lol

Update: is there a way to test the low pressure switch i.e. should there be continuity when testing the 2 pins inside the switch?

I was wondering if it could be the valve on the AC pipe. It's like a tyre valve and when I press it in I get a squirt of air/gas, seems to be ok.
If I can't buy the old style low pressure switch anymore I might try a used one, but want to confirm mine is definitely not working via a continuity test etc. So I can tell the difference.

Could the pressure be the issue where by it's not giving enough pressure to activate the switch, and so not activating the compressor. Although I had the gas checked at Halfords where he said it was full just after only 2 squirts.