w115 owners, for goodness sake, check under your fuse box!

[pizzachef]

I'm having an intermittent electrical issue. Every so often, maybe once a week or so, the headlights get brighter, and if the blower is on, it starts blowing faster, and the dash lights all get brighter. I have no idea what could cause a surge like that. Also, sometimes a belt squeals, but none really feel that loose. And it'll happen just cruising down the road, all of a sudden it'll squeal for a it, I let off the pdeal, it stops, it might do it again, then its gone.

So I bought a voltmeter so I could at least have something to watch when it happens. I unscrewed the fuse box to attach the + wire for the gauge to one of the switched +12v wires in the fuse box and look what I found.

Here's the fuse box:


Here's under the fuse box:


So I cleaned out all the leaves and crap and found some deteriorated wires


There's also another bad wire up in the bundle that didn't make the picture. I spliced a new piece of wire into that one. I traced that really badly deteriorated wire at the bottom, and it goes to fuse #3, which had no wire on the other side of the fuse. The fuse map says it goes to the automatic transmission, which I got none of So I disconnected it from where it comes from (a little box above the fuse box with another fuse in it ). The last deteriorated wire goes to another little box above teh fuse box with another fuse in it, but I just wrapped that one in electrical tape for now. I want to get some heat shrink tubing for future repairs to this area. For now, all I had was regular crimp connectors.

So that's it, I thought I'd pass on to everyone what I found.

[strelnik]

Originally Posted by pizzachef

The last deteriorated wire goes to another little box above teh fuse box with another fuse in it, but I just wrapped that one in electrical tape for now. I want to get some heat shrink tubing for future repairs to this area. For now, all I had was regular crimp connectors.

So that's it, I thought I'd pass on to everyone what I found.

Much obliged! I just bought a good, but dirty 220D with a lot of little issues and this is one place to check out.
It's also another item to add to the Great 220D Maintenance Inspection Checklist for people buying and/or restoring them!!

[280EZRider]

Excellent tutorial! This is probably why, in subsequence series, MBZ mounted the fuse box on the firewall with the back connections inside the car.

[meltedpanda]

wow , wonder why you were not blowing fuses left and right!

[diametricalbenz]

Wow, I am sure mine is filled with pine needles.

[Kpmurphy]

Wow thats crazy.
Should all the fusses be white but 1? A while back I got some of the brass fusses.

[pizzachef]

Originally Posted by Kpmurphy

Wow thats crazy.
Should all the fusses be white but 1? A while back I got some of the brass fusses.

Yea, I bought a pack of new fuses with the intention of replacing all the old ones and never got around to it. Everything works so I'll probably leave it be for now, but if I have problems, I'll put in the new fuses. The placard on the inside of the fuse box lid says what size fuse to put where, and as far as I know, they're all correct. I should double check though. It does seem funny that so many are the white ones.