electrical fault, wiper motor stopped working , Heater light flashes ?

Changed two side lights topped up oil ,water,coolant , red light came on to say it was over heating , temperature gage at top. a week later , wipers stopped working ,can hear wiper motor,rear heater light flashes on and off,sometime hear sound of wires meeting.fuses OK , garage think it may be the main unit
Renault megane 1997 diesel 1.9 turbo

Julie Saunders
January 2009