In my 1987 300e, only the dome light works. when i open the door, all the normal lights turn on as they should. but when i went to go drop off my little brother at a sleepever tonight, none of the lights turn on such as the backlight for the dashboard like the speedometer/fuel tank/ and oil pressure. none of those lights work. in addition, none of the light for the temperature control such as a.c and heater don't work as well as the radio lights. i have tried moving the dimmer and that does nothing. my guess is that it is a blown fuse... shoudl go ahead and replace all fuses right now because of wear??? any other possibilities to why this might happen? oh all the functions work, i brought a flashlight and checked that they all work, radio works fine, ac works fine and so do all the gauges... ideas??
** UPDATE **
ok.. well i looked into my fusebox and found out there was no fuse at all for fog lights so i put one in and now they work

they are tooo yellow though, icky. ill work on that later, maybe they will be super high beams... the possibilities!! well for the third fuse which is for :
parking/taillight right,headlamp cleaning unit, Illumination : license plate, instrument,control climate
ok when i looked in, this was fuse was blown. so i replaced it with the correct one, i forget the value but it was the white one, and when i put it in, i checked again later tonight and it was blown yet again. i am thinking this could be the cause of the license plate light not working, as well as all the inner lights and right brake light.... so what are the causes the the fuse being blown? can this be a diy project? any ideas would be appreciated.