Relay source wire

[USA64]

Asking for myself; is there any reason two fused cannot be used?

[MarkDa]

No reason not to - we do it domestically in the UK with a large fuse on the ring main to project the cabling and a smaller fuse in the plug to protect the appliance/user.
The same could apply in a car where a main cable feeds a couple items.
Two fans could be run off one controller and separately fused so the failure of one doesn't kill the other (my daughter's Astra does just this actually - very sophisticated as it compensated by running the other at top speed!)