Right brake light comes on by itself when parked

[ratovan]

Hello,
I have a Palomino Stampede 2006 Hybrid trailer.

Recently after coming back from a camping trip we unhooked the trailer as we normally do but a day later the right rear brake light came on.

I hooked up the trailer to the tow vehicle through the electrical outlet. Hit the brakes and the light went out.

A week later the light came back on.

The bulb gets hot so I have since removed it.

It looks like I have a short somewhere but I don't know where to start. Any hints?

Thanks!

[wmtire]

It would seem like it would have to be getting power from your trailer battery somehow.

My first thought would be a wire has come loose in the umbilical cord and is touching the 12 volt + terminal (#4 in pic), since it right beside the right hand light terminal. (#6 in pic)

Maybe it just enough that when you plug it into the vehicle it doesn't touch, but when it is unconnected it does.



You might can trace the umbilical cord on the trailer back to a junction box, and see if something has come loose/frayed there.

Also I might recommend checking the emergency breakaway switch and see if anything is loose/corroded there. You are not pulling the emergency breakway cable out to use as a parking brake, are you? I don't think the actual lights are connected to the electric brakes but would need a wiring schematic to be sure.

[ratovan]

Originally Posted by wmtire

It would seem like it would have to be getting power from your trailer battery somehow.

My first thought would be a wire has come loose in the umbilical cord and is touching the 12 volt + terminal (#4 in pic), since it right beside the right hand light terminal. (#6 in pic)

Maybe it just enough that when you plug it into the vehicle it doesn't touch, but when it is unconnected it does.



You might can trace the umbilical cord on the trailer back to a junction box, and see if something has come loose/frayed there.

Also I might recommend checking the emergency breakaway switch and see if anything is loose/corroded there. You are not pulling the emergency breakway cable out to use as a parking brake, are you? I don't think the actual lights are connected to the electric brakes but would need a wiring schematic to be sure.

Thanks!

I took a circuit tester out and sure enough the battery lead and the right turn signal lead where hot (power going through them).

The 7 way on the trailer doesn't seem to have any way to remove the connectors to inspect the wiring. Do I assume that my only recourse is to cut off the 7 way plug on the trailer and replace it?

[wmtire]

Originally Posted by ratovan

Thanks!

I took a circuit tester out and sure enough the battery lead and the right turn signal lead where hot (power going through them).

The 7 way on the trailer doesn't seem to have any way to remove the connectors to inspect the wiring. Do I assume that my only recourse is to cut off the 7 way plug on the trailer and replace it?

Well, the 12 volt + should be hot as that goes to your battery in the RV, but the right lights shouldn't.

You may have a molded plug on the end of your umbilical cord. However, I would still follow the cord back on the trailer frame to where it probably enters a junction box. Your trouble could be at that end of the cord. I would definitely check there before trying to cut the 7 way plug off the cord.

Are you using a circuit tester that just lights up, or perhaps a multi-meter that shows how many DC volts are on the right light? The reason I ask is you could have another problem, that is a lot more complicated and I don't want to get into at the onset. It would entail your frame being hot. Let's stay with the simple stuff first.

Just for grins, did you also check the brake wire (#2 in the pic above) to be sure it's not hot too in the 7-pin connector. It shouldn't be.

Something else to try, is to put the bulb back, then start wiggling the cord and end to see if the light goes out (or turns on if it isn't lit up). That may help you determine where/if the 12 volt hot wire and right light wire are touching each other.

You may want to disconnect the battery first before reinstalling the bulb, so it doesn't blow out when you put it back in. Once you reinstall the bulb then hook the battery back up and start wiggling. LOL

I have to wonder if gravity is the problem. When you have the 7-pin plugged into the tow vehicle, then gravity would pull a possible loose right light wire inside the 7 pin down and away from the 12 volt + terminal. Then if you just let the 7-pin hang after disconnecting, then gravity may actually pull the right light wire over to the 12 volt + terminal. You should be able to test that theory and move the plug into different positions (horizontal and vertical) to see if the right lights go off/on.

[ratovan]

Originally Posted by wmtire

Well, the 12 volt + should be hot as that goes to your battery in the RV, but the right lights shouldn't.

You may have a molded plug on the end of your umbilical cord. However, I would still follow the cord back on the trailer frame to where it probably enters a junction box. Your trouble could be at that end of the cord. I would definitely check there before trying to cut the 7 way plug off the cord.

Are you using a circuit tester that just lights up, or perhaps a multi-meter that shows how many DC volts are on the right light? The reason I ask is you could have another problem, that is a lot more complicated and I don't want to get into at the onset. It would entail your frame being hot. Let's stay with the simple stuff first.

Just for grins, did you also check the brake wire (#2 in the pic above) to be sure it's not hot too in the 7-pin connector. It shouldn't be.

Something else to try, is to put the bulb back, then start wiggling the cord and end to see if the light goes out (or turns on if it isn't lit up). That may help you determine where/if the 12 volt hot wire and right light wire are touching each other.

You may want to disconnect the battery first before reinstalling the bulb, so it doesn't blow out when you put it back in. Once you reinstall the bulb then hook the battery back up and start wiggling. LOL

I have to wonder if gravity is the problem. When you have the 7-pin plugged into the tow vehicle, then gravity would pull a possible loose right light wire inside the 7 pin down and away from the 12 volt + terminal. Then if you just let the 7-pin hang after disconnecting, then gravity may actually pull the right light wire over to the 12 volt + terminal. You should be able to test that theory and move the plug into different positions (horizontal and vertical) to see if the right lights go off/on.

Ok I am going to follow leads around today with the tester and find the short.
Thanks for pointing me in the right direction!

[wmtire]

Ratovan, I forgot to add that the reason I stated the position #'s when referencing the pic, is that RV's usually have a different wiring color coding than other trailers. This is why I didn't say anything about the color code of the wire.

If you do trace to the junction box, then you may notice that the brown wire is for your right hand lights and not the green one (if you went by the pic I posted).

It's easy to look at the pic of the plug end and test the correct terminal, but however, when you go to the junction box, then you are only going to see color coded wire..... which will probably follow the RV color code pictured below....or it may not and follow the one for other trailers. The positioning/function is the same either way, just the wire colors are different. Don't ask me why they couldn't make it simple. LOL

[Harkerr]

Check where the pigtail connects to the trailer wiring. Prime spot for a short. Look closely at all the connections.