2005 Renault Clio Fuses

Electrical problem
2005 Renault Clio Two Wheel Drive Manual 91000 miles

I have had a number of problems over the years with my car that have always come down to my fuse box getting wet. This has included car cutting out while driving and loss of acceleration. Now my engine managment light keeps coming on and staying on for only about 30 seconds before going off again the temp gage on dash shoots up and down as well. Could this be caused by the fuses again or do I have a real problem. The car is still driving fine and only clue that there is an issue is that when car is powered down fan in engine is really loud as if working really hard. Hope you can help.