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U1300l
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Discussion Starter #1
I've tried what I thought was obvious, but my 1250L just can't get any electrical power. It ran fine, parked it, now I can't get it to start or light up the gauges.

I tried another battery, nothing. I tried jumping it, nothing.

I tried jumping to the starter and grounded on engine frame, still nothing.

The curious thing here too, I don't get even the slightest spark when I connect either the battery cables or jumper cables.

Is this just a complete lack of ground? F'd starter?

I've also reset all the breakers on top of dash, so no joy there either.

I could really use some help here.

Thanks
Todd
 

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BenzWorld UNIMOG statesman
Unimog 404.1 Diesel (sold :( )1995 LMTV 1078
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5,856 Posts
allways... allways..... its something stupid :D

Sounds like someone turned the battery disconnect switch to off. Turn it back to on and you'll have zooom zoom. On the older mogs switch was just under front edge drivers seat on the floor. Not sure if this location stayed sorta standard on all mogs or not. It does have a key.. not like an ignition key. just a "L"ed piece of round stock with a special end.
 

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U1300l
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Discussion Starter #3
I've not seen one on this one, where would it be located? The thing is that it was parked in the shop when it went from running to dead.

The only thing that changed was that I cleaned up the engine, but I'm usually pretty careful.
 

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BenzWorld UNIMOG statesman
Unimog 404.1 Diesel (sold :( )1995 LMTV 1078
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5,856 Posts
coachconverter said:
I've not seen one on this one, where would it be located? The thing is that it was parked in the shop when it went from running to dead.

The only thing that changed was that I cleaned up the engine, but I'm usually pretty careful.
Sorry I don't know where it is on that model. I can pretty much bet there is one though and it certainly fits your symptoms. Try following the big battery cables and see where the switch is. Battery is usually wired straight thru the disconnect switch.

Only other thing I can think of is a major ground... welll..... no.... there is one other. On my mog I had one fuse blow... that fuse (my memory might be sketchy here but) ... would not let the dash lights go on, running lights go on OR let the starter do anything.... hmmmm...
 

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U1300l
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Discussion Starter #6
Finally got a chance to try to trace down the problem, with a voltmeter:

Checked battery = 12v
Checked power at the starter post = 12v
Checked mains going through firewall on both sides = 12v
Checked ignition switch leads = 12v
Tried another ignition switch = no joy

Stupified....

Again, put the key in, turn and no lights, no movement, no start, no nothin...

arghh
 

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BenzWorld UNIMOG statesman
Unimog 404.1 Diesel (sold :( )1995 LMTV 1078
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ok..... back to the simple stupid things. Check the fuses. On my mog I had a fuse blow that took out my running lights, starter, and a few other minor things you don't notice till 10 or 15 mins later while testting things for juice and feeling stumped in the middle of the night at a gas station in the middle of nowhere. Does that sound like a been there dont that story LOL
 

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U1600AG + a LR 90
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coachconverter said:
Sounds like fun...

It has breakers and I've tripped and reset them all several times, to no evail.
Err there will be one or 2 breakers on the dashboard face, but the fuses live under a cover on top of the dashboard above directly above the instruments (LHD), the cover is about 17” wide x 3.5” long x 0.5” high, there will be 2 racks of fuse holders and each rack has 12 fuses, the left rack is “A” and the right rack is “B”.

From past experience I can tell you that the fuse joints become dry and dirty over time to the point ware they will brake contact and not allow a circuit to be made or can burn out the contact points on the end of the fuse witch you wont see until you remove the fuse, fuses F5 and F6 in rack A (427’s) are common ones as they service the starter interlocks and most of the dashboard lighting and powering up, also on mine there are some relays witch are triggered by the ignition switch witch then power up circuits, the relays are behind a metal plate just to the left of the clutch pedal near the lower door hinge.
 

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U1300l
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Discussion Starter #10
Another hour or two working on it...

I've taken the voltmeter to check power from battery, to starter, to ignition, to main breaker (button on dash), to relays. There is power all the way to the relays located under the breakers panel. Tried some new relays too, but still no luck.

I'm out of ideas here...
 

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4Sale: 230G, U1200 Ag, 1017A, lots of MB cars, Volvo c303, 416 raildoka, LR D110 TDi
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I've been trying to think of something else that could be causing no power on the dash, but I can't think of anything else other than what was suggested to try that wouldn't involve tracing the wires through the dash. I guess if worst comes to worst, You can send it down when you pick the two here at the shop up after they are fixed. I know I could figure it out if I could look at it and test various things in the wiring.

Cheers,
Ben

P.S. Todd, I got the 406 running... now for the stopping :).
 

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U1300l
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Discussion Starter #12
Sounds good Ben,

At this point, I'm willing to punt on it. After dropping the steering wheel, removing the dash and replacing every relay and breaker, I'm whooped. Of course, after all that work it will probably be something like a switch or chaffed wire, but I've looked at what I can.

Good news on the 406, how's the "stopping" efforst coming along? I could use it back here as a mule... too many newer, fancier, more expensive Mogs sitting around here, that need to be towed from place to place :)

Todd
 

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Sold .....1987 U1250 Unimog
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Old issue, New owner

Interesting Thread ...... I would really love if anyone has anymore insight into this issue.....

Seems I am now the owner of this Unimog with the issues described.

Last weekend I drove the Unimog down the road, say 15 miles with no issues. Turned the key off and pulled the gas pedal up to kill the motor.
Went inside came back out turned key... nothing off on still nothing. with the key in the on position nothing works, and I mean nothing, no fan, no lights everything is dead.


In the end I crossed the started to get it stated, Great Unimog is running but no lights, no tach, no fan, nothing electrical under the dash. About 1/2 way home it... Electrical stated working all of the sudden.

This has happend to me 3 times now, and well its a little un nerving.

Thanks everyone for the help
 

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BenzWorld UNIMOG statesman
Unimog 404.1 Diesel (sold :( )1995 LMTV 1078
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that kind of thing is usually a major ground wire. or a major electrical junction area like those mounted to the side of the frame on many older rigs. Least thats from my limited experience.

Clean all your big grounds. IN particular the battery cutt of switch. Check all you major junction/distribution blocks.
 

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Sold .....1987 U1250 Unimog
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There is no ground switch to my knowledge on this Unimog. Civilian Unimog

From Memory the ground wire goes from the Battery to the left shock tower which is just under the front cab mount, it appeared Ben ground down that area and reinstalled the wire, I suppose corrosion may be festering there, under the connection.

Does this sounds like the correct location for a ground wire?
Should it go elsewhere?
Where does the engine get grounded?
Seriously thinking about replacing both heavy cables with some factory replacements and or custom built with machine crimped on connections. But I don’t know if that would be worth the $$$ or time.
 

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1991 1250L Doka Unimog, 2002 ML320
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Dave I think it's because your truck is Yellow. My White doesn't seem to have the problem. Really though my truck did have some corrosion under the frame lug, you couldn't see it because it had a nice coat of black paint over it.
Chas
 
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