not sure if the system hardware is the same as the 4x4 saph l8 but the pins ar the same designation as the p8.
on the 4x4 saph pin 21 should has a 12v supply from fuse 18 which is routed through an de-iceing switch in the aircon cooling plenm, this switch cuts the aircon system if the plenm ices up by removing the voltage at pin 21
relay m11 on the saph is the idle speed compensation realy for the aircon and is earthed through pin 12,and this in turn gets its supply from the magnetic clutch relay.
i can send you a copy of the diagram if you wish it may help as the same pins are involved and i would guess that the rest of the system is similar.
its possible you have a simple wire short to ground or just a wrong connection made