To much wires all around the engine

Hi there,
I’ve a question about the electric diagram on my V12.
I do have an XJS V12 from 1989 on my E Type. I’ll be rebuilding the car soon.
I’m wondering what is the use form the “Idle Relay”, “supplementary air valve” and “compressor relay”.
I assume that these parts are dedicated to the engine idle when there is the charge on the engine because of the air conditionning compressor. Am I right ?
My goal is to simplify the wiring loom and just keep the wires for the EFI.
thanks for any feedback

Michel - - basically yes, you are right

this page on the Jag-lovers site may help a bit –

And Sean Straw excellent write-up here

Thank you for your information.