Question

How do I find out which fuse is for what in my rapide swift 490 gxl 1994?

Answer

The fuse panel will control the 12 volt system. There will be one for the water pump (normally 10 amp), one for the lights (normally 5 or 7.5 amps), one for any 12 volt sockets (normally 10 amp) and if fitted one for TV aerial amplifier, electric rooflight etc.
Remove each fuse in turn to discover what each controls.