Backup lights stuck on.

[Giggiwatt]

I need some help.
I just brought home a new to me 2010 Classic 31
.
When we previewed the trailer the batteries were no good and the trailer was hooked to shore power. Upon new batteries and hooking the trailer to my truck, the backup lights were stuck on on both the truck and trailer, and I have no running lights. The dealer didn't have a tech available, it was getting late, and we were 5 hours from home on borrowed time with a babysitter and we really didn't want to make the 10hr round trip twice.

When I disconnect the trailer plug, the truck reverse lights go out on the truck, but the trailer reverse lights are still on. I assume the truck lights are being back fed by the trailer.

Now when I got home, I flipped the master disconnect in the trailer to kill power from the batteries to turn off the lights and the reverse lights were still on! I had to disconnect both batteries to shut them off.
Any ideas where to start with this?

[Giggiwatt]

Ok, I just plugged it into shore power and noticed the backup lights are still on even when hooked to shore power. I have to get this figured out asap.

[dcopps]

Seems like the common point for backup lights and power is at the umbilical. I would start by looking for a short in the plug. The manual shows for US models, the backup lights are not fused at the distribution panel so it wouldn't be there.

[Jim & Susan]

Not sure what that physical plug looks like on the insideof your camper, but on our '73 the wires are exposed with only a thin plastic cover. I've always worried that something would fall against it during travel and short the lights or brakes.

Ours is mounted center of the front panel, just a couple inches above the floor.

Might post a picture or two. Light problems are common it seems like. I'll bet somebody has had this exact problem before.

Good luck.

Jim

[Jekerrville]

The issue is the backup wire and the battery charging wire inside the 7-way connector to the tow vehicle are shorted to each other.

Take a very small flat blade screw driver and back out the small screw on the barrel of the 7-way connector. Then there should be a larger screw where the wire from the AS goes into this connector. Back it out to free the wire and slid out the innards.

You will find that the backup light wire and battery wire are shorted or the backup wire has slipped out of its connector and shorted to the battery wire.

Clear the short. Put everything back like it was and go in peace and sin no more.

[Giggiwatt]

I'm pretty sure you guys are onto something with the plug being shorted. It doesn't appear that my plug comes apart though. I lifted what I believe to be the 12v+ charge wire from the distribution block and the backup lights went off.

However, I tried to jumper 12v to the green wire in the black box and still get no running lights. Is there a fuse or breaker anywhere hidden?

[dcopps]

It is odd that the jumper didn't light the running lights. Make sure the battery disconnect is not activated

To check for a short in the plug. Undo the umbilical wires at the black box and use a multi meter to check the resistance between the wires. This should verify if you need to replace the plug.

[dames7]

First, throw away your battery, they are shot.

[Giggiwatt]

Well, It seemed as though i was getting continuity across certain pins at the plug when i wiggled the wiring. I was pretty sure that was the issue so i replaced the plug. Nope. Still have the same issue.

When I lift the black charge wire from the block the reverse lights go out. But as soon as i plug the truck in...Bam! Reverse lights on again.

[Giggiwatt]

So I isolated both ends of the 7 pin cord. I've got continuity between the yellow and black, and an open green. Going to have to replace the entire cable. I can't seem to see anywhere where the cable was damaged externally though.

In the meantime I ran the yellow to the green to supply 12v to the running lights through the shorted cable. I'll have to leave the black charge wire disconnected so the running lights won't stay on, but that will at least make it legal to tow until it's properly repaired.

[dcopps]

Probable someone drove a screw thru the cable. Who knows. How accessible is the cable to replace?