>>28452661
nvm re-read OP. sounds like what you need is a mini fuse socket connector, pic related. you can then get an inline switch and if it has wires included, crimp a female terminal on each wire then stick that into the connector.
if the fuse socket is located inside a fuse box and there's not enough clearance for this (or in a remote place like the engine bay) then see if you can release the terminals from the socket on the back side of the box so you can reroute the wiring or add wiring to route it to an easy to reach spot