How to test trailer runnimg lights witout hooking

[Montana_2230]

I read some where on another forum where someone built a plug for the end of the trailer brake/ power cord . Using this plug allows you to test all the running, brake and turn lights without hooking up the cord to the tow truck. Anyone know how to do this? I have done a google but can't find anything. Thanks.

[jerryb]

All you need is a 12 volt source, positive and negitive and test leads.
The easiest way is to hook up the truck, but you could use any 12v battery or a converter.

[mallardjusted]

But of course this would only prove the trailer lights and wiring are good, and you would still need to make sure the physical connection to the tow vehicle is good when you get ready to hook up. From my experience, the connection is where I've had many more problems.

[Montana_2230]

I was just trying to do a quick and dirty job of finding out which running lights I have out. Noticed on our last trip home I had a couple of them not working and I forgot which ones. Just didn't want to go to the trouble taking my king pin tripod down, backing up and hooking up the truck cable. I am lazy I guess.

Anyway thanks, I finally found a diagram of the plug, so It will be no problem.

[Sunseekers]

I have driven up along side of the 5th wheel close enough that the plug would reach and gave my battery a boost while running the slide out. You could do the same to check your lights.

[NJ Hillbilly]

You can also make a jumper wire that goes from the battery charge terminal on the plug to the circuit You want to test. If You check the plug with a test light or meter You will find a terminal that has 12v hot. Jump this terminal to any other terminal (except for ground) and the circuit will be energized. You can check running lights, left and right turn/brake lights, even the electric brakes.

Search for rv 7-way wiring diagrams and you will have the info You need.


John

[Montana_2230]

That's how I did it NJ Hillbilly...thanks

My cord is too short to hook up with my tripod in place on the king pin.

[kdeiss]

In the terminal box on the hitch I put a switch to jump the battery to the running lites.I flip this switch and it lites all the running lites kind of cool looking at night at the camp ground.This way I can check out all my lites except the turn signals.

[sgf]

kdeiss,what terminals on the plug do you jump to do this,have seen it done with a fuse with pigtails but forgot to ask what terminals you have to use ,thanks.

[RnR]

... or you can try this,

Buy a heavy duty flasher, the type you use on turn signals. They usually have two male spades on them. Plug it into your trailer plug on the spade that has 12v on it. It will begin to flash all marker lights and tail lights on and off. Easy to find out if any are not working.

Another neat idea for this is, if you have company coming, and they have not been there before and you are parked in a well hidden spot, just tell them to look for the trailer with the flashing running lights. (RV.net forum)

WARNING: These flashing lights may irritate some neighbors !

Garry

[Gene Chaltry]

RnR....Your right, the flasher works very well. Have used that for many years on my TT to check the lights. There is a slight pause before it begins flashing. Looks real neat.

[Montana_2230]

Garry and Gene, Not sure I undersstand how this works. Is a spade a prong? If it has two spades/prongs on the flasher and you plug one into the 12 volt slot, where does the other prong go? Could you please go into a little more detail for an electrical dummy like me. Sound like it's exactly what I need. Thanks.

[H. John Kohl]

There are six pins on the outside ring of the plug. Looking at the top there is one on each side to the top key. As you look at the plug the one on the right is the charge battery or 12v source and the one on the left is tail and running lights. The two pronged "older style" flasher has there prongs set so they will plug into the 12 and running lites sockets. In an emergency a small NR 12 gage insulated jumper will also work.
Base on a previous posting I have done the same thing.
Good luck.

[sreigle]

Sounds like a good way to check the lights but I hope none of you leave the flashers in place all night in a campground. We used to frequent a state park where a guy left the lights flashing all night. Quite irritating when sitting out under the awning and even when trying to sleep. Those flashing lights come right through the shades.