Generator 12 volt supply

[CZSteve]

We have a 2008 Jayco Melbourne 29D that's new to us and we're completely new to RV's.
We knew going in that the Onan 4000 generator was bad when we purchased the rig; spun crankshaft.

We removed the old generator and bought a used / rebuilt Onan 4000.
Installed the new gen yesterday ~ 3-weeks after removing the old generator (life got in the way some...)

Problem / Question:
I don't see any 12-volt cable to attach to the solenoid and for the life of me I don't recall removing a 12-volt supply from the old generator.
NOTE: Before we completed the RV purchase the dealer installed two new coach batteries (battery compartment is immediately next to the generator FWIW) - I'm 'assuming' the dealer may have removed the 12 volt cable when replacing the batteries but just an assumption but would explain no cable found.

1. For the 12 volt supply is it just a simple matter of running 6-8 gauge cable from one of the coach batteries positive post to the solenoid terminal as-shown to red arrow in below pic? Other?
2. Also - Are there 2ea ground cable that should be attached to the generator ground lug?
- Red arrow is ground cable off frame.
- Green arrow of cable in corrugated sheath runs into wire loom under frame; volt meter reads 12V with negative lead to this cable & positive lead to positive terminal on coach battery.

Thanks again for any insight.

Best,
Steve

SOLENOID TERMINAL FOR 12V POSITIVE (RED ARROW) - JUST A STRAIGHT RUN FROM BATTERY OR OTHER?

NEGATIVE CABLES - CORREGATED (RED) TO CHASIS WIRING LOOM / NON-CORREGATED (GREEN) TO CHASIS (NORMAL GROUND - BOTH TO GENERATOR GRND TERMINAL?

 

[Kevin Cooper]

I’m color blind, mostly, but the top cable in the second picture (red?) looks to be the one you need to take to the solenoid in the top picture. That small wire on the solenoid stud is most likely getting power from the connection, not feeding power to it. From the top cable in picture 2 does it have battery volts to ground or not. If not, check for inline fuse at or neat the battery. If it does, connect to the stud and start her up!

 

[Grumpy]

That's what the install instructions say to do.

 

[mini4mw]

I just happen to be messing with a starter solenoid so I can give some advice-

There should be a small wire going to the solenoid that has 12v when you hit the switch to turn on the generator. This engages the solenoid to connect two large wires together. One from the house battery and another going to the gen starter. Probably at least 6 gauge.

The starter solenoid usually just attaches to metal with brackets and that is the ground (solenoid has metal back/holes you screw into the metal chassis). This may have a ground lug. Since the power is coming from the house batteries to start, you need to complete that circuit. Generator and chassis on a single ground connection.

 

[Kevin Cooper]

Per Grumpys drawing, that one in pic 2 goes to the solenoid stud. The other one is the output 120 volts.

 

[CZSteve]

From the top cable in picture 2 does it have battery volts to ground or not. If not, check for inline fuse at or neat the battery. If it does, connect to the stud and start her up!

Correct, red arrow for top corrugated line.
I initially did connect this to the solenoid thinking same that it was the positive lead; no power.
When I use my volt meter with the negative lead to this corrugated wire and positive lead to positive battery terminal I have a solid 12-volt reading. I am NOT an electrician by any stretch but to my limited knowledge does this not ID the corrugated as a Ground?
And seems weird that a ground wire would be in a corrugated sheath.

Thanks again for any assist.

 

[Kevin Cooper]

Pull both of the conductors with end termination loops off. Measure for volts from each to the metal frame. Whichever one shows battery voltage gets connected to the solenoid. The one that does not is negative.

 

[craigav]

...
And seems weird that a ground wire would be in a corrugated sheath.

Thanks again for any assist.

Just an important heads up,
Your ground wire is not in a corrugated sheath (aka a split wire loom), if you check your 2nd image again, the ground wire is the only wire not in a corrugated sheath. ~CA

 

[CZSteve]

OK - pretty sure the corrugated cable has to be the 12-volt 'Positive' and assuming a blown fuse. Note: Didn't have a tech install; did as a DIY and 'assuming' the positive lead might have come in contact with a ground which IF did is a 'bone-head' move on my part; so hoping it's just a blown fuse I can locate before going down service call road.

So... as mentioned; this corrugated cable runs into a large under-chassis wire loom and do not see any visible circuit-breaker under the chassis. I've checked the coach fuses and all are good; my son is about to check the cab fuses.

Any idea as to where the fuse for the generator 12-volt is located on this rig?

 

[Kevin Cooper]

The + cable to the start solenoid comes directly from the battery location. There will be no breakers or fuses under the coach. Usually red plastic in line fuse or breaker visible from battery.

 

[Grumpy]

The + cable to the start solenoid comes directly from the battery location. There will be no breakers or fuses under the coach. Usually red plastic in line fuse or breaker visible from battery.

And the OP may not have it on the right battery terminal.

 

[CZSteve]

OK / Stand-Down - Found a positive battery cable that had broken from the battery post lug apparently when the dealer changed the batteries... and of course we now have 12-volts that corrugated cable and up & running; or at least trying to start - was priming & think flooded the cylinder but we're cranking over. Letting set for a bit.

Thanks again of the help and putting up with me / Best, SA

 

[Kevin Cooper]

Those gens are typically a hard start. You might give it a sniff of ether if you can’t get it to start. I mine takes seems like at least 15-20 seconds before it will start.
At least you are now getting closer!