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??

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.

Well for starters you have to figure out everything that fuse supplies power to. and it looks like you have found the majority if not all.

Then unplug all the items and put a fues in.

If you found them all it shouln't blow rite away.

Then plug one of the things in and operate it. If the fuse is ok then go to another item and plug it in and evaluate the fuse.

Do you see were I'm going with this? When the fuse blows start suspecting the item you last pluged in.

This works very well if the fues blow rite away. But is a bit harder if its blowing intermetintly.

For all lamps that are acessable just pull the bulb. That wont tell you if its the wires but its most likely a bulb/socket or wires at the door seem area. Unless you just had u-haul wire a trailer light set up for you but I doubt that.

You also have a interior light relay for the interior lights and door buzzer.....You also have a Light control Relay I don't know anymore about either of these relays but I just parted out a 1987 and a 1990 300E and they both have them...Jim

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James A. Harris

where do i go to connect and disconnect wires to check them???

Well sense you asked that question I have to say.
In almost every town there is an auto electrical shop that has been in busness for 20-30 years and every shop in town sends there electrical problems to them.
This shop is usualy very honest and you should seek that shop and ask them for a bit of help.

Don't be discuraged if they cant give you an exact estament because they can't.
Electrical problems have to be diagnosed with a process of elimanation and (experenced hunch) method.

They will prob. say well just spend an hour and then let you know were we are at. If that first hr. doesn't give them enough time to diag. and fix it. (it usually does)
then you can go from there.