Fuse keep blowing? Mirror Switch not working?

Possibly caused Check the wiring for the washer jets under the bonnet, repair/clean the connectors, replace the fuse and test.

The mirror has a friction/spring joint. On the underside of the mirror near the joint there is a small black plastic cover held in by a drive pin. Under this is a 'nut' which determines the friction in the mirror joint. An unconventional nut which needs a special tool to tighten. It is a thick round nut with an internal thread and two holes in it, requiring a special key to tighten it.

The black plastic cover is virtually impossible to remove without breaking and is NLA. Use a long nosed pliers to tighten.