If it is not one thing it's another "Electrical problems" - PeachParts Mercedes-Benz Forum

coachgeo · #1 08-07-2003, 09:20 PM

I was messing with re connecting the additional 3 fuel tanks on my MB Unimog and after a full day of messing with it I had an engine that Konkt out like fuel starvation or air problems,. It would not restart. 30 min. later I hooked everything back to just the one tank like it has been set up for the last year.... took a little while to start it but it ran just fine. Very disapointed... blows a shiat load of plans right out of the water

I had a dash light stay on that usually doesnt. the light seems to be something to do with the alternator/power. Before this was converted with this diesel motor this light I believe would stay on if the "generator" was having problems. Yeah..... one of those lights that come on as your starting the motor but once it fires up it goes off. hmmmmmm.... I had no electrically powered gauges either.. hmm

Turned the rig off... went to turn it back on.... Wont start. Wont turn, Wont click, just SILENT. All the fuses seem fine. Other stuff works though

I have what appears to be half of the all electrical (head lights, fans, 12v fuel pump, etc. are fine. Just not power to dash stuff, NO VOLT METER, NO STARTER BUTTON power. I have glow plugs!(seperate starter and glow buttons are used since this was once a gasser)

I found a junction where several Large hot lines converge right near where I was doing alot of work. Grouding to a grounding strap near by they all showed to have juice. I'll recheck if that ground strap was strab from cab to frame or cab to cab. Mog 404's have ground straps all over the place. Even the doors have a ground strap body to body.

So question is..... Generally speaking.. what should you look for when you loose half of your electrical components, but other half seem fine and so do the fuses?

VERY frustrating day...

JimSmith · #2 08-08-2003, 08:10 AM

coachgeo,

Don't know about Unimogs, but the sedans have the power for many of those functions go directly to the light switch, and from there to the key operated starter switch, and from there to a variety of places for the functions you are missing. I would try looking at that area, or back track from the items that are dead. I think they all come to a single place though. Good luck, Jim

P.E.Haiges · #3 08-08-2003, 10:25 AM

Coach,

It very difficult to diagnose an open circuit with out a wiring diagram. You should try to get one.

P E H

coachgeo · #4 08-08-2003, 10:46 AM

I have one. Hard part is there is so much customization done on this thing.

I was hoping some gereralities might exist in this particular area.

Suggestions like Jim's allways are great help.

coachgeo · #5 08-08-2003, 02:40 PM

I followed some wires tracing sources of things which brought me once again to the fue box. I moved some wires to inspect things and..........

Low and behold... hidden in there was a blown fuse. Glass fuse with the sodder blasted against the glass in such a manner that from one angle it looked to be a complete circuit across the fuse cause the sodder on the glass made it look like the element inside was intact . At least in a dimly lit situation like last night was, the element looked good

Well at least that is my excues and Im sticking to it!!!

I connected a jumper to replace the fuse and my volt meter on the dash returned.

Sooooo..... then I got a fuse put in and started it up. Will just have to wait and see if it blows out. I still could have a short or something that is blowing the fuse.