Yours sounds like a damp/wet fuse box,,,
Normally, it is, take the fuse box out, ( the one under the bonnet)
Battery off,,,,, then fuse box cover,,, then the nut/pin, coming from the red positive lead going to the fusebox..This needs undoing. and lifting out the way..
The fuse box then needs maneuvering out to get at the multiplugs, these are held on by plastic tabs, these tabs need pressing in..
Be careful and look closely at each multiplugs as some have two tabs that have to be pressed...
Once the multi plugs are off, inspect closely for any green ( verdigris) looking pins..
Spray your multi plugs and connections with electrical contact cleaner..
Avoid penetrating oils, such as wd40, if at all possible, on any of your electrics,, as this builds up a film, and as renault do not like any excessive resistance through the wiring system, another problem arises after the penetrating
starts to dry, between the two contacts