laguna dci stereo and dash wiring problem washer jets also

hi there i have a 2002 renault laguna 1.9 dci and it has recently developed a few faults. first the stereo has gone off but also the dash illumination bit at the top of the dash, also when i pull my windscreen wiper arm forward for some water the washer squirts the back wiper but nothing at the front.

ive checked the stereo wiring and there is still a live there i have also looked at the back of the heater switch and the switch has been burnt, so i have purchased another switch module and this will hopefully be ok but ive no idea weather there is a serious problem with the wiring or wether the heater switch has a part to play so if any one out there can help me i would be most greatfull

i would appreciate any help thanks very much

gareth