Tail Light Always on

[Peto]

Very strange. I was out by my trailer that is stored on my side yard and plugged in to a 30amp service. I noticed the right tail light was glowing. It's not a full tail light but appears to be just one center bulb. The trailer is not plugged into my truck so no clue where it is getting the power from.

Anyone ever see this before. I've had the trailer on the side yard for a while and never noticed it after dark. I would have noticed it before anytime I walked behind the trailer at home (often) or while camping.

Don't these lights get their power from the truck?

Only change recently was the addition of a second lithium battery and a smart shunt.

Short somewhere? I'll pull the light tomorrow and look for any obvious corrosion but I'm sure there will be none since the unit is only a year old and I live in the desert.

Any insight guys?

[notanlines]

Any chance that what you’re seeing is a reflection of sunlight?
Or are you seeing it at night also….

[dutchmensport]

Here is an image of your trailer pig-tail plug that plugs into your truck:



When using a jumper between #4 and #3 and you are not plugged into your truck, all your running lights will turn on, on the camper. The power is coming from your camper converter (breaker and fuse box).

Before dismantling "stuff", I think you should start with that plug. Follow the wire to where it connects in your camper. Take the cover off and make sure there are no wires that have rubbed the insulation off making contact. It's possible that "hot" wire (#4) could be touching a frayed (#6) wire causing the light to glow all the time.

I would start the search there as that is the first point of contact that could cause the problem. Start at the beginning of the flow, not at the end to eliminate issues.

[ChuckS]

Your 2023 should have the Giggy box installed .. this is an upgrade from the typical junction box where the 7 way RV cable that plugs into truck is connected

1st pic shows what it looks like and second pic shows the wire diagram to trouble shoot that lit tail light

[JRTJH]

Like Chuck, I'd suspect a short or a "stray wire" probably in the Giggy Box. Take the cover off and look closely. For "grins" I'd loosen each of the 7 wires (backup lights aren't used on most Keystone trailers) and wiggle them, then retighten the connectors on the screw posts, and recheck the tail lights.

You're right, those lights and the running lights "if things are working correctly" get their power from the tow vehicle via the 7 pin umbilical. But as all those wires "meander aimlessly through the belly and ceiling of the trailer" there may be an "unintended short between wires"... BUT: usually when it's a short, the single bulb or LED you see ought to be "full bright". It's corrosion or bad connections that usually cause "dim, partially bright lights" ... So, probably a loose connection and the most likely place is in the Giggy Box.

[Peto]

Thanks guys!!!

I checked again this morning and the bulb is still on. I have been messing around with an attempt to install a bike bunk on the front of the a frame and did move a couple wires out of the way to get to some mounting bolts.

I've never opened the giggy box though so will pull the cover and see if I can find anything obvious as well as jumping the plug to make sure everything activates.

notanlines - it's glowing bright all the time, night or day.

JRTJH - please define a "grin". I've never heard that term in electrical work. I know I don't do much grinning when trying to diagnose an issue like this

[sourdough]

Originally Posted by Peto

Thanks guys!!!

I checked again this morning and the bulb is still on. I have been messing around with an attempt to install a bike bunk on the front of the a frame and did move a couple wires out of the way to get to some mounting bolts.

I've never opened the giggy box though so will pull the cover and see if I can find anything obvious as well as jumping the plug to make sure everything activates.

notanlines - it's glowing bright all the time, night or day.

JRTJH - please define a "grin". I've never heard that term in electrical work. I know I don't do much grinning when trying to diagnose an issue like this

The red above is probably where your issue arose. See where those wires go and if there wasn't that had a loose connection and pulled into another one.

[Peto]

Fixed... Thanks to the suggestion to start at the beginning instead of the end

I have a rubber cap that I put on my 7 pin connecter when not in use to keep out dust and grime. I pulled it off and the plug was covered with some kind of grease and I assume making a slight connection between pin 3 and 4. No clue where the grease came from other than the factory as this is the first time I have ever seen it and assume with the plug hanging down and in the excessive heat we have been having it liquified and ran down to the face of the plug and into the cap. I assume its dielectric grease but I have no clue. It was light blue in color.

Anyway, I cleaned the plug and the cap of any grease and the light went out. Plugged in the truck and all lights work fine.

Mysteries abound when it comes to electrical issues
(I'm glad I did not screw something up to cause the issue...)

Thanks again. It's nice having a resource like you guys to walk me through issues as they arrive.


Thanks again

[JRTJH]

Originally Posted by Peto

Thanks guys!!!
....
JRTJH - please define a "grin". I've never heard that term in electrical work. I know I don't do much grinning when trying to diagnose an issue like this

For "grins" (just to make yourself happy and smile)... When things aren't "well defined in theory" sometimes, just going out on a limb and checking things that in your gut feel like they could be a possibility (a hunch) is doing things "just for grins"....

[LHaven]

Dielectric greases are nonconductive by design. There are conductive jellies like No-Ox (orange) that an owner might use on (say) battery terminals. Following up on the source of this blue substance might be advisable.

[Folkie]

Originally Posted by Peto

Fixed... Thanks to the suggestion to start at the beginning instead of the end

I have a rubber cap that I put on my 7 pin connecter when not in use to keep out dust and grime. I pulled it off and the plug was covered with some kind of grease and I assume making a slight connection between pin 3 and 4. No clue where the grease came from other than the factory as this is the first time I have ever seen it and assume with the plug hanging down and in the excessive heat we have been having it liquified and ran down to the face of the plug and into the cap. I assume its dielectric grease but I have no clue. It was light blue in color.

Anyway, I cleaned the plug and the cap of any grease and the light went out. Plugged in the truck and all lights work fine.

Mysteries abound when it comes to electrical issues
(I'm glad I did not screw something up to cause the issue...)

Thanks again. It's nice having a resource like you guys to walk me through issues as they arrive.


Thanks again

I also have a rubber cap on my 7-pin cable. You need to be careful and hang it upright so rain water will not collect and short out pins. Do not just drape it over the A-frame. BTDT