12 Volt Batter Hookup Question

[Billy_Hill]

I picked up this 21 foot Fun Runner Toy Hauler. The battery box has two wires that I don't know what to do with. The two (white) wires are heavy gauge and in the same sleeve as the main hot lead.

I can plug the 110 in and it looks like everything works. I can run it off the battery and it looks like everything works.

When I have the truck hooked up to the plug, the interior electrical does not work but the lights do work.

In the attached picture I don't know if the two white wires hook up to + or -.

[RJsfishin]

If I was forced to connect any white wires at the battery, I wouldn't get anywhere the positive terminal !!
And if for some stupid reason someone really did use white for positive, I still would not connect them until they one way or tother change color to red or black !

BurbMan wrote:
They may be wires coming from the converter that charge the battery when plugged in. Typically the ground is run through the frame (like a car) so chances are those are both (+). If you have a multimeter, set it to ohms and see if you get any continuity between either of those wires and the frame, just to rule out them being grounds. You may want to crawl around a little and see what you can find out before connecting them. Or maybe call the guy you bought it from and ask him?

Oldman....ya gotta lay off the hooch this early...what "hotties below the picture?"

[wa8yxm]

I agree with the person who said "Commonly White in an RV is ground" however the key word in that phrase is "Commonly"

And normally only one wire connects to the battery negative, This wire also connects to the frame and all other ground connections are made to the frame.

So any "extra wires" are usually positive.

And of course this helps not at all

Find out if anything does not work,, Jacks, Brakes (Break away, if it is a trailer for sure one of those leads is the brakes) and such... Meter the leads, see if there is 12 volt on them when plugged in.

From there you may get a clue.. When you find out label them

once you get it all hooked up get a can of RED spray paint (Any size you like includign Testor's model paint) and spray the POSITIVE end of the battery, wires and all.. Then you will know next time.

[CA_Traveler]

Put red tape on the wires to the + terminal and black on the - terminal wire. Then remove and clean the lugs and battery post. When you figure out what the white wires are for then add colored tape to them especially covering the colored lugs, attach and take a picture.

With a new rig I start taking pictures of anything I can see, wiring, equipment, labels, etc and keep them in a backed up file. Great reference material.

[edbehnke]

good ideas but unless you know electrical i'd suggest you get someone to look at it....you could burn the trailer down if you short a wire. spend the money, that is what trailing is all about.

or, where did you buy it? talk to them, someone there knows what is what.

[DaHose]

Grab your multimeter and do a continuity sounder test to ground.

Jose

[BurbMan]

LOL gotcha!

Billy, if that wire got really hot when hooked to (+) then I agree with BruceMc it's probably grounded to something, or there's a direct short in whatever it's connected to.

In residential wiring, black is hot and white is neutral. In vehicle wiring, black is ground and any other color (including white) is hot. RV is a mix of both so you need to stay on your toes where wiring is concerned.

This may seem silly but are you sure the battery is connected properly? Both sets of wires are black...

Sounds like you are in for some detective work!

[Billy_Hill]

I first tried to use Tinypic.com to put up the image but it didn't take, so what ever hotties you saw were not my doing. Sadly. 🙂

Thanks for the help. I'll trace the wires and check if they're connecting to ground.

[time2roll]

I would remove all wires and discover where they are connected before attaching to the battery.

Generally white is ground and black or color is positive. However there are many exceptions... especially on used RVs.

Get out your voltmeter and verify continuity to ground before you connect to the negative. Then plug in to find what becomes 12v+ etc until you know what everything is.

[2oldman]

BurbMan wrote:
Oldman....ya gotta lay off the hooch this early...what "hotties below the picture?"

When OP first posted, his url was different...would not display. I went to his url and saw 4 hotties below his picture.

[BruceMc]

Commonly in RVs, white is ground. Chase those wires to see where they go. If it got hot connecting it to +, then it is a dead short to ground. Hot diggity!

[Billy_Hill]

Burbman, I'll hook up a multimeter to it this afternoon. The battery charges when plugged in to 110. Not when plugged into the truck.

I'll hook up the multimeter to it when I get home. It got REAL hot when I tried to connect that red connector to +.

Thanks for your help.

[BurbMan]

They may be wires coming from the converter that charge the battery when plugged in. Typically the ground is run through the frame (like a car) so chances are those are both (+). If you have a multimeter, set it to ohms and see if you get any continuity between either of those wires and the frame, just to rule out them being grounds. You may want to crawl around a little and see what you can find out before connecting them. Or maybe call the guy you bought it from and ask him?

Oldman....ya gotta lay off the hooch this early...what "hotties below the picture?"

[2oldman]

I was distracted by the hotties below your picture.