Wiring help- Round relay by three fuse at drivers side engine compartment
 

Hello,
Could any one tell me what the round relay with 5 wires, (two red, two brown and one blue) its for. And where does each individual wire go to. This is the round relay located in the engine compartment drivers side at the rear. On the holding plate which also has the rear window defoger and three fuse block.
I looked at the diagrams but did not see this relay.
Thanks in advance,
AL

It's the rear engine blower fan relay (on a sc) bentley pp 971-5. No diagram on how the engine blower system is wired, in the Bentley

Thanks,
My car is a 74 with cis.
Does any one have the wiring diagram for the relay.
Thanks,
AL