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12v accessory circuit problem.

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Wayne461
Posts: 776

12v accessory circuit problem.

Post#1 » Mon May 16, 2016 6:19 am

Good morning gentleman, I recently wired a 12v accessory curcut on my military 461. I wired the curcut to the first, or grounded battery to a separate 12v fuse box. I attempted to connect a power port so I can charge my cell phone, and planned to wire some interior lighting. When I turned on the master switch, the fuse to the power port blew. Am I missing something? As I said, the 12v curcut is wired to the positive, and negative terminals on the first grounded battery in the 24v system. There is a relay box of some sort wired into the 24v master switch. Would that have something to do with the problem?
Wayne C Pickhardt
waynecpickhardt@gmail.com
1988 Danish army? 461-240/300GD ..Frankenstein.

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vadimivanovich
Posts: 8643

Re: 12v accessory curcut problem.

Post#2 » Mon May 16, 2016 7:19 am

Pretty hard to say without seeing the schematic. Use a voltage meter to verify that you're actually getting 12V going to your power port. Also, check polarity.
"The way you think is the way you live"

Wayne461
Posts: 776

Re: 12v accessory curcut problem.

Post#3 » Mon May 16, 2016 7:25 am

I'm getting 12v from the fuse box I installed, unless the power port is internally grounded -shorted. I didn't check for that as it's new, out of the package. Funny how when I turned on the lockout switch last time the headlight relay burned up.
Wayne C Pickhardt
waynecpickhardt@gmail.com
1988 Danish army? 461-240/300GD ..Frankenstein.

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vadimivanovich
Posts: 8643

Re: 12v accessory curcut problem.

Post#4 » Mon May 16, 2016 7:33 am

Hmmm. Sounds like an investigation of your lockout switch is in order. Still, I don't see how the application of power to a device could just make it burn up. Even at 24v, the relay shouldn't care about polarity. The power port certainly would though. Check the port on another vehicle first.
"The way you think is the way you live"

Wayne461
Posts: 776

Re: 12v accessory curcut problem.

Post#5 » Mon May 16, 2016 7:38 am

I think a complete 12v conversion in order, and do away with the 24v system completely
Wayne C Pickhardt
waynecpickhardt@gmail.com
1988 Danish army? 461-240/300GD ..Frankenstein.

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Atl-Wagen
Posts: 915
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Re: 12v accessory curcut problem.

Post#6 » Tue Mar 26, 2019 5:37 pm

So is there a headlight relay on the W461? Both of my low beams are out, and one of my high beams is out, [oh and when it happened by wipers went crazy, and I burned up the blower fuse] Does anyone have W461 wiring schematic? Circa 1988.

Thank you for your support, and I do have the W460 230GE diagram, but something tells me they are different.
W460-230GE- Sold
W461-617A Sold

85' W460 280GE Cabrio

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AlanMcR
Posts: 7729

Re: 12v accessory curcut problem.

Post#7 » Tue Mar 26, 2019 7:00 pm

Any time multiple electrical problems happen at one time look for grounding issues. I'll bet that there is a common ground between these circuits. Unfortunately, I don't have the W461 wiring diagram. The MB wiring diagrams will show which grounds are connected together and where.
...Alan

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vadimivanovich
Posts: 8643

Re: 12v accessory curcut problem.

Post#8 » Tue Mar 26, 2019 7:04 pm

Sounds like a ground problem Locate and clean/grease all of these before doing anything else. There are many hidden grounding points. First in line is the single heavy non-insulated cable that goes from the battery to body to frame to Transmission housing - without breaks! Also check inner fenders, inside the dash under the instrument cluster, and by the trailer hitch on the frame. There may be others, such as the ground isolator switch in your center console, under the clock.
"The way you think is the way you live"

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aircruiser
Posts: 719

Re: 12v accessory circuit problem.

Post#9 » Tue Mar 26, 2019 7:55 pm

Just another thought. When you say power port, are you talking about usb? If so, most USB ports are polarity critical.

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offroad-world
Posts: 9813
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Re: 12v accessory circuit problem.

Post#10 » Tue Mar 26, 2019 10:44 pm

sounds like the blinker switch to me , when they break often weird things happen with wiper horn and lights .

mfg. guido .
300GDT OM617A Kastenwagen, 2850mm wheel base
250GDT OM602A Single Cab, 3400mm wheel base , gone to friend Orest

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