micky1963

Last night I went to put one of my passenger windows donw and all the interior lights got really dim and then all the lights in the dashboard and all the lights in the window bottuns went out
I have checked the fuses and their are no fuses burned out is their some sort of relay that I should also be looking for now since the fuses in the fuse box are all ok
Car model 300e 1986
Guys thank you so much
PS the headlights work fine blinkers and all are fine what happened?

124-Fan

Hmm.. Sounds like the dimmer switch, behind the instrument cluster.
-There´s a small knob you can turn in the dashboard, which increases or decreases the brightness of the lights in the dashboard and the buttons.
If you pull out the instrument cluster( using a flat and thin screwdriver to pry it forward ) and disconnect all the wires from it along with the speedometer cable, you will see a small white plastic piece on the back side of it. This is the dimmer switch. There are thin metal contacts on it which often break, due to old age and heat. You can solder it back together. -Check it out. It´s very common.

Jer

First of all I would NOT recommend using a screwdriver to remove the instrument cluster. The padded dash can be easily damaged. You are better off buying the removal hooks for ~$25. Part number 140 589 02 33 00.

Second, the dimmer is white porcelain, not plastic. It's not a big detail, but someone new to the back of the cluster might confuse this for a big piece of white plastic; the speedometer.

micky1963

Guys I have checked all the buttons on the dash board I know about the swithch on the panel that dims the light.I was having issues with one of the window buttons in the center console everytime i try to put the window down it would blow the fuse so I didnt replace the fuse or touch that button any more but one of my kids went into the car and touch the button and everything blew out now I dont have light in the dash or on any of the window buttons so at night everything is dark inside
So I was wondering if besides the fuses in the fuse box their was some sort of may relay that could have blown
That is what i am looking for some sort of relay that controls power to all the items like the dash light and the lights for the buttons for the windows on the console
If their is a relay that may have blown which allows all this things to get power
Like I said all fuses are ok but is their another main relay that may have blown

124-Fan

Well, what can I say. I´ve done it at least a 100 times using a suitable screwdriver. Never damaged it. Naturally with the required caution.
And the dimmer switch is made of plastic.. -That´s why you have to be careful when you solder the metal plates together.

124-Fan

The lights in the window buttons are connected with the lights in the dash, so when the dimmer switch fails, all these lights go out.
-But the power circuit to the windows is separate through the window switch. So if pushing the switch keeps blowing the fuse, it hasn´t necessarily anything to do with the lights in the buttons and in the dash. That might simply be the window motor stuck, etc.

micky1963

Well thank you it sounds like you are sure of what you have mentioned
so i will look into the switch
Also quick qestion as far as the button for the window blowing the fuse
when the fuse is in a brand new one the window does go up and down but just a few times then it blows the fuse does it sound like a short somewhere and as soon as I use it it blows after on or two up and downs of the window ?

micky1963

Do you know where in the car this relay would be ?\I also attached a picture or at least uplaoded attached to this post

Item Number: MB058224
Main Category: MERCEDES-B
Sub Category: ELECTRICAL
Qualifier: 300 E 1986 - 1992
Description: Relay
For Instrument Lighting
Manufacturer: GENUINE
List Price: $75.00
Your Price: $ 63.75
Core Price:
Weight: 0.170
Per Car Qty: 1
Quantity Available: 1

124-Fan

As to be expected, there can be several reasons for the fuse blowing. But first of all I´d suspect the window motor itself being old and stiff and thus drawing more current, as a result of old age and perhaps lack of use.
-I have never experienced this relay going bad, but of course everything is possible. But it costs you 63.75$ to find out, doesn´t it ?
-So if you think you can get the cluster out and examine the dimmer switch, that won´t cost you anything. Except a little time and effort.
-But keep in mind what Jer said. The instrument cluster can sometimes be a bit stuck and if you haven´t done this before, you naturally might damage it while trying to remove it. That is, unless you have the “preferred tools.”

-I´ll look up the location of the relay tomorrow.

Cheers,

micky1963

Thank you so much for your time
I do realize that this is all free info that will eventually save me some form of money
So in return I say thank you again
I will check with you tomorrow

124-Fan

Well then, according to my MB wiring diagrams, this relay does not belong to the instrument lights.
I´ve made a simplified diagram, showing roughly how it´s connected.
Current is received from the lamp switch to the dash when you turn the switch on, via one of the poles in the round multi pin plug in the back of the dash.
From there it goes through the dimmer ( rheostat ), to the dash lights as well as the other lights. Such as the window button lights, etc..

Cheers,

micky1963

O k then last question since you have made sure to rule that out by the way nice pic it puts everything into the correct order
Question I am thinking of removing the dash instrument panel
How would I go about doing that any key things I should keep in mind when disconnecting in the back and how or where would I start to pry this part out
By the way you realize that all this info is so vaulable to people like me this site is great

micky1963

I was able to pull it out with no issue at least out of the hole with your advice of a screw driver just two little minor dings on the console nothing big you cant even notice it
BUT IT SEEMS SOMETHING IS PULLING IN THE BACK SO I CANT DISCONNECT OR GET MYHAND BEHIND IT how do i get it to come out all the way
if you tell me you have to walk me thru what i may have to disconnect to get it out since I have no idea
I heard of the speeddometer cable in the engine but dont have any idea
UI am so close yet so far

Jer

DON'T PULL HARD! Remove the carpet in the footwell and detach the black speedometer cable from the clip on the floor. Pull up a little more cable from the floor, and the cluster should slide forward more. Stick your hand behind there and unscrew the round collar on the cable.