12V wiring problems in 13' Burro

[Armymomma]

I'm going to throw this out here & see if anyone can give me the "Idiot's Guide to 12V wiring problems".
I decided to add an additional 12v light in my 83' Burro right next to the Heater Control (on the side of the closet). THere are 2 12 volt lights on either side of the kitchen cabinets & they worked fine so this was simply going to be splicing into the existing black & white wires & connecting the new light.
Welllll.... All was going well UNTIL... i accidentally touched the white & black wires together -- PSssfts! - the lights went out -- all 3 sets -- the sink lights AND my new addition.
I found that there was a single "in line" fuse under the sink that connected the Black pos(+) wire. I thought I had simply blown the fuse but, no. The fuse was replaced & still no lights. For grins, I bypassed the fuse by splicing the the black/pos wire together & still no lights (so, probably not the fuse, right...?).

I took my new light & went outside of the trailer & touched the wires to the pos(+) & neg (-) leads on the deep cycle battery. The light lit up - yea!
I went back in the trailer & tried attaching the wires from the light to the Black & White wires under the sink. NO LIGHT!
I went under the front bunk/couch area of the trailer (driver's side) & attached the wires to the 12 V Battery wires (again, neg & pos leads coming straight off of the 12V Battery) &, VOILA, Light came on again.

3 questions:
1) While doing this, I noticed that the Neg (-) wire from the 12 V Battery was capped where it entered the trailer & nothing was/is attached to it.
Why is this?

2) After attaching the light's wires to the neg & pos wires from the battery, I kept one attached to the black (pos+) lead from the 12V battery & the attached the other wire from the light to the WHITE WIRE ( the GROUND from the 7 pin connector) as shown in the Burro Manual. NO LIGHT! If I move the wire off of the white ground & put it back onto the Neg wire coming from the battery, I am able to get the light to come on again.

3)Why do the 12V fixtures incorporate the white ground wire rather than utilizing the neg wire from the battery?



WHAT AM I DOING WRONG HERE ?????? Why am I not able to get the current flowing once I wire everything back up the way it was originally (Black Pos+ wire from the battery plus the White 7 pin ground wire)???
I'm making myself crazy over this!!!

Also, can somebody/anybody tell me what they think happened when I crossed the wires & originally lost lighting? That would probably be helpful, eh?
PUHLEAEEEASE tell me WHAT IN THE WORLD I'M MISSING HERE!!!?????

This seemed so simple -- replace a fuse, get back to work, right? NOPE!
HELP PLEASE before I yank all the wiring out & re-run everything!!!

MANY thanks in advance for the help (please keep in mind that I'm no electrician when you send answers -- remember the "Idiot's Guide" part )

[mary and bob]

sounds like you lost a connection somewhere when you shorted out the wiring. you need a simple automotive test light and trace the wiring to narrow down where the problem is, most likely in a connection somewhere, or another fuse. Start where you do have power and work out from there.

[floyd]

Are your house lights grounded to the frame instead of directly to the battery? If so... then check the negative wire from the lights for contact with the frame, then check the negative wire from the battery to the frame. I prefer to wire the "house" wiring from the Positive post through a fuse panel with all grounds returning to the battery through wiring.
I recognize that frame grounding is acceptable and that chassis ground is normal in automotive applications, but on fiberglass trailers I think a ground harness makes more sense, since grounds are the biggest source of DC difficulty.

[gcssr39]

Most new vehicles have a fused circuit to the trailer connection , look in the main fuse compartment, you will probably find a fuse blown, also tell us what tow vehicle.
Go to your wireing diagram, check source of trailer 12volt power to the 7 pin plug. Run a 12volt source of power to the fuse in the trailer (one wire 12v) does it supply light power. Hope this helps;;;;;;;;;;;;; Grant

[Armymomma]

Whew!! Thanks a bunch for all the help!
Really appreciate the "clue" regarding fuse on the tow vehicle.

This is what I found/how I fixed my little problem:
- Neg (-) wire from trailer battery was shorted out. Replaced wire & connector.

- In line fuse was blown ( this was under the sink area, part of the black (pos +) wire inserted prior to black wire going into 12 V cabinet lights). Replaced the fuse tube.

-10 Amp fuse under hood of Tow Vehicle (2007 Honda Element) was shot. Replaced 10 Amp fuse. Note: I was unaware of this fuse's existence. I had already pulled all the fuses under the dash board but didn't think to look under the hood for a blown fuse so THANK YOU for the clue!!!

Status: "Little Beast" is all better & the New 12v light is up & running too.

What should have been a 20 min job turned into 2 days of head scratching & lots of language I was glad my kids weren't around to hear BUT... Now I know the wiring for my baby backwards & forwards, lol, & have a stash of extra fuses tucked away for any future gaffs!

-almost to the point where I can roll it out of the garage & get some pics for posting.

Thanks again for the terrific help & super quick responses to my (latest...) dilemma ;o)

[gcssr39]

Thank you for the quick reply to the help offered, so many forget to thank the people for helping. Grant