The Sanden compressor was never factory fitted to any HK-WB Holden. They always fitted the GM/Delco/Harrison A6 unit.

GM-H did however offer a 'genuine' dealer-fitted a/c system for HX-WB, utilising the Sanden SD508 compressor. This was the system where you lost the rear half of the glovebox.

Where the confusion arises is that GM-H did use the Sanden SD508 compressor for the factory-fitted a/cond system in VC/VH Commodores.

AFAIK the low pressure switch mentioned is now a legal requirement in all states of Australia when retrofitting a/cond systems.

Dr Terry