Aircon not working

[malcthom]

AC ceased working abruptly on 2003 E53 3.0d! Not good when 36C outside!!
Relevant fuses are intact.
Compressor will not kick in when AC selected at head unit. It will rotate easily by hand so not seized. Also aux fan will not run. Have checked and have power to aux fan. Have not checked low & high side pressures of system as yet.
Just wondering whether a faulty automatic aircon sensor unit (part #64116917001) that sits on the main fan shroud, would shut down both the aux fan and compressor? Also will the compressor run if aux fan not working? Have read ALL the forums re this and no consensus of opinion.
Are there any relays controlling the two also?