2004 Renault Scenic electrical fault

My Renault would not start when I returned to it one day I got RAC to tow to RAC approved garage and they said it was the fuse box and after cleaning it up they adviced to get a new one. I got a second hand one from my usual garage man and it was ok for a couple of week. I then went to Asda and on returning to my car it did the same thing so again I got RAC out and they again couldn't get it running so I asked for them to tow me to my garage I use. The garage man said the stop/start fuse was blown and gave me a couple in case it did it again. Which of course it did I have had to change it several times and took it back to garage to see what blowing fuse garage changed the fuse box again and within an hour of getting it back it blew again. Then it started to do something else coming up with parking fault only for a minute when I released it manually it was ok. Then all weekend it was fine no blown fuse no faults. This morning I took my son to school and on the way home it come up with electrical fault then parking fault steering fault and every other fault going I quickly took it to garage and he put it on machine and it said stuck relay and he couldn't sort till Wednesday. He said it would be still ok to drive thought. When I got home I could not even get the car to turn off and it was flashing every fault it could imagine up and the wipers were swishing away when the stick was not even pulled down I had to put it into first gear and stall it to turn it off. I then went to try it a few hours later and everything was ok I even managed a two mile trip before it happened again. Does anyone on here know how to help me please