97 golf vr6 air con faults

just wondering if anyone out there has air con on there vr6, it
stopped workin then it broke down.. i changed the compresor as the
barings had gone but it wont seem to work im thinkin its a sensor
somewear but as i cant find any wire diagrams for it its hard to find
the right sensor to fix, oh an if anyone has to have the timin chains
done its v expensive...