The number 7 fuse on my 84 300 D keeps blowing out. that is the one that controls all the lighting, inluding all the window and airconditioning buttons as well the instr cluster. anyone have any ideas on what it could be. if it is a short any ideas on where to start looking. aslo i recently changed my radio and i just kept the brown wire that used to provide light to the radio(and is linked to the fues well) insulated but disconnected. can this have any effect on the fuse??.

Greetings Turbo,

Can you give more details as to whether the fuse blows as you try to put it in, after something is powered up, the ignition key is turned etc. Need more details to help.


Charles

__________________
"Tell me and I will listen, Teach me and I will learn, Show me and I will accomplish, Involve me and I will succeed."
'84 300SD 256,000 Gold on Brown (Mileage Award)
'86 300E 246,000 Blue on Tan

Here is the details: My head lights are linked to all the lighting inside the cabin (except the dome light and the rear courtesy light.) the fuse stays intact when i power up the car but when i turn the headlights on, consequently powering up all the inter-cabin lighting then the fuse goes instantly. the head lights stay on ( i guess because they are on a different saftey circuit.)
Hope this information helps.

Greetings Turbo,

The number 7 fuse should be for the RH high beam headlight, and fuse 1 is for dash lights. If this is true try unplugging the RH headlight then use the light switch and see if that blows the fuse. I also once saw a broken piece of fuse metal cause a ground from one circuit to another in the fuse box, so double check that the box is free from debris causing a short to ground. Let me know what you discover from this. Remember that fuse 1 and 7 should be white in color at 8 amps.

Charles

__________________
"Tell me and I will listen, Teach me and I will learn, Show me and I will accomplish, Involve me and I will succeed."
'84 300SD 256,000 Gold on Brown (Mileage Award)
'86 300E 246,000 Blue on Tan

If fuse 7 is for the dash lights I would question what you hooked the gray blue stripe wire to when you replaced the radio? This is the factory illumination wire for the radio not the brown wire. The brown wire is the ground. I would go back to what you did last electrically and double check it!

Scott@LaJollaAudio

__________________
The Mercedes Specialists Since 1986

OK 10^6 apologies! it was not the #7 but the #1 fuse that blows out. I must have misread the number the first time. i will check the radio wiring again and see whats going on.
thanks for all the replys.

Greetings,

I feel like Scott, I think that a power lead to the radio has accidently been grounded. I'd relook over the installation of your new tune box as well as your schematic of the car and tape off the appropriate wire.

Charles

__________________
"Tell me and I will listen, Teach me and I will learn, Show me and I will accomplish, Involve me and I will succeed."
'84 300SD 256,000 Gold on Brown (Mileage Award)
'86 300E 246,000 Blue on Tan

I hit the curb when parking and it bent one of my horns up against the frame, shorting it and blowing fuses.

Thanks guys, scott was right, apparently the brown wire was in fact the ground so i now hae the grey blue(radio illumination wire) open but insulated. However, now the instrument panel lght i really dim and the buttons still dont light up. the P, R, N ... lights on the shifter light up but nothing else. The fuse stays intact.

I am glad you found the problem. The next problem sound like a bad dimmer control. This happened because of the direct short on the illumm wire. Step one is to pull the cluster and jumper across the dimmer and see if the lights go to full brightness. If this is the case then you can get a new dimmer for @ $30.00 at the dealer.

Scott@Lajollaaudio

__________________
The Mercedes Specialists Since 1986