Strange wiring in 87 RV

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  #1  
Old 08-30-10, 09:48 AM
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Strange wiring in 87 RV

Elderly neighbor has an old (good condition though, only about 30K orig miles) RV with odd wiring. Here's the basics...
3 batteries in the front behind grill. 1 is for the engine, 1 is for the gennie, 1 is for aux lighting and accessories inside.

He asked me to take a look and try to find why his gennie battery wasn't charging. Well, turns out his genset isn't one that charges it's own battery. No windings and no regulator...so that was easy. It was already starting to get hot and humid so I didn't follow through a whole lot on what I'm going to describe next. He is in no great hurry anyway.

Well, looking at the wiring around the batteries (it's a rat nest, 4 owners and lots of add ons) he has 2 high current solenoids wired to the genset and aux batteries. It appears that when they are energized they might put the 2 in parallel. There's a heavy duty momentary switch that looks user installed on the dash and has a wire leading to one of the solenoids (reads ground), other side of switch has wire leading to ground on aux battery. The other solenoid has a single wire leading back into the engine area (I think) also reads ground. I'm guessing either someone removed some other wires and possibly the wire leading to the battery is wrong?

Now, never owned a Ford, but these look kind of like a starter solenoid. 2 heavy battery connections on opposite sides, and 2 smaller connections for the control voltage and ground (though they appear to be grounded through the mounting screws as well)?

The aux battery stays charged (according to him) so I assume it is charging from the alternator when driving or inverter when on shore power?

My thought is that someone installed these (button doesn't look factory, dash hole is kinda ragged) in case the gennie battery was weak, you could jump in the aux battery by pushing the button to start it? Then take it back out of circuit to prevent draining the aux down?

I know you need to have some sort of isolation between the systems so you will always be able to drive off if needed.

I know how to trace wiring and check continuity, but I'm not sure about the 'noids. Can I disconnect the battery leads, then use a 12V source on the 2 smaller terminals to see if they energize? I didn't remove them, but I also couldn't see any markings (kinda hard to see the bottoms in the confined space). I don't want to really have to remove everything and keep track of all the wiring to bench test unless I have to.

I know it's kind of confusing, I'll clarify if needed, but I'm working off memory as he is gone for a while.

Thanks
 
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Old 08-31-10, 09:44 AM
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Nobody? How about at least telling me if my thinking on checking the solenoids is correct?
 
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Old 08-31-10, 09:15 PM
Join Date: Jan 2007
Location: North Central Indiana
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wiring

There are three types of solenoids. Grounded base where you put power to one wire to energize. Insulated base where you ground one wire to energize. and another where you supply ground and power to two terms to energize. On a mess like this I just get out the wire cutters and strip everything out. Then put it back like you want it you will save time over trying to figure out what has been done. As you see no one has jumped in cause there is no way we can walk you thru something like this. Hope this helps some. RW
 
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Old 09-01-10, 07:18 AM
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OK...so I really need to get then out of the circuit and find out what they are. Thanks for the reply..that helps.
 
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