i first measured voltage at the n280 valve with the multimeter on the feed and grounded it to the chassis. i also measured it using the other terminal on the plug .,same reading. i also belled the earth from the plug to where it connects on the n/s chassis leg.

 

when i removed the binnacle i grounded the multi meter on the battery and spliced the yellow and black wire to get a reading whilst everything was plugged in

I think you've demonstrated nicely that the wiring is all OK.

my heads busted.. i drive a truck for a living lol

 

My vehicle had no fault codes, not true, initially it showed the G65 sensor faulty (common fault) I replaced it, system was charged showing correct low side pressure, no compressor shut down codes, Climatronic telling aircon to work, modulated signal being sent to pressure control valve but no rise in high side pressure just like you.

 

I removed the pressure control valve freed it off (not sure it was even stuck) bench tested it, seemed to be working and paid for a regas, no different bought a new valve, fitted it, regas again still no pressure rise

 

Fitted new chinese compressor £108 delivered and it worked

 

Stripped old compressor and it was like new inside, very simple, could only have been a blocked gallery and they were all clear, I will never know if it was at fault or the replacement control valve was faulty, if your system works by driving it from the test box then the fault must be either a compressor shut down code or faulty wiring.

cheers  j.r 

we have fitted a new n280 and a new high pressure switch too. 

 

the cold side pressure was 55 psi which i belive is too high. but suspect its because the compressor isnt running

 bbut when he connected his device to the n280 valve it all worked fine,fans cold air etc?. odd

Low side pressure is temperature dependant, also my guages show guage pressure and VCDS shows absolute pressure which is 14.7 psi higher, 55psi is not unreasonable.

 

I think the VCDS shut down code if it shows one will be definitive.

 

If its working, or thinks that it is working then you can watch the compressor loading (think thats the term) going up on VCDS which would equate to a higher modulated voltage being sent to the control valve, you should be able to measure that rise at the connector, in fact I think VCDS shows the voltage.

 

I cant believe that I went 14 years with my MK1 Octavia without needing VCDS, its indispensable on the more complicated MK2 and from what I have seen of the garages generic readers even £3000 Snap-On ones they dont have the detailed stuff like the compressor **** down codes.

i know what you mean. will try the solaris if no joy will have to pay my mate again for the vcds diagnosis

quick question is this any good guys. maybe worth buying

 

https://www.ebay.co.uk/itm/VAGelsawin-dealer-level-and-VCDS-diagnostic-tool-for-Audi-VW-Skoda-Seat/323743782172?hash=item4b60a2151c:g:18YAAOSwc0lckOO5&frcectupt=true

 

gonna keep the car and take it to portugal when i retire hence ac working

Edited 19 March, 20197 yr by rockabilly

RIGHT UPDATE.......lol

 

let me firstly thank everyone on this thread for there help.cheers guys.

 

so today took the skoda for a solaris scan at a friends garage. when we went into hvac codes came up showing

temp sensor left and right footwell open curcuit  B108415 B108315. also temp sensor evaporator outflow open curcuit  B10A915 and B10A915 activation a/c compressor open curcuit/short curcuit to positive

 

last week we had the vcds plugged in and i thought he cleared all codes?. all i have done since then is do the climatic flaps reset on the panel in the car. so maybe these code are that. or maybe he didnt clear the hvac codes. but once they were cleared and rechecked to be clear. the system works  as it shoud.

 

switch a/c on and at around 10bar refrigerant pressure the fans come on both at slow speed

 

current valid compressor shut off condition is compressor active

refrigerant pressure sensor normal

compressor speed 900

comp load 3.2nm

comp current actual 0.815(a)actual fan activation 10%

 

so really i could only think the n280 i replaced was faulty and due to the codes not being cleared in the hvac screen the new one would not work.

 

just drove home with the heating on. stopped the car opened the bonnet.no fans on. turned temp to full cold and switched a/c and with a minute fans came on slow speed.

 

i am a very happy bunny..

 

 

cheers guys again.

A great result but a mystery nonetheless.

 

Did you check the compressor shut off condition before erasing the fault codes? That would probably have revealed what was preventing the Climatronic from activating the compressor.

 

Great feeling to finally win though, or at least it was for me!

49 minutes ago, rockabilly said:

i am a very happy bunny..

Great news mate, well done.  

cheers guys.

 

no j.r unfortunately my mate was too keen on the solaris

 

 

been driving everywhere with the a/c on lol