Need Help - No Running lights

[Andy]

’07 3400, I have power to the pin box, suspecting a short, or maybe a fuse? Is there a fuse or box other than the one on the bathroom? Thanks in advance, Andy

[JimF]

Had that problem, it was the trailer connector, had to replace it. The one on the truck, not the trailer. Do you have park lights working on the truck?? There is a truck fuse for that and it would effect the trailer. No trailer fuses for it on my 2007 3400RL.

[H. John Kohl]

Andy,
You comment about the bathroom. The internal 12volt system in the trailer is independent of the outside running lights. There is a 4x4" square box on your hitch pin. Check that box for a loose wire nut.
Good luck.
Let us know what you find.

[Andy]

OK, yesterday I had a mobile repair guy out here to look at the problem, he checked the 4”X4” square box on the pin, said there was power to that point. He traced the wire until he lost it in the body, and said to find the wiring diagram for the unit, and he’d be back. Then, as John suggested I checked the box, and to my untrained eye and unknowing mind, all looked good. Except there is a single white wire that is screwed to the box that to me might appear to be the ground wire? There is one of those crimpy things attached that could appear to have moved (although I could not move it) and bare wire is exposed right where it disappears into the box. Could this possibly cause the problem? I tried to put some electrical tape on it but there’s no room to get it around the wire. Thanks’ again, Andy

[Slufoot733]

Andy,

IF the ground wire is loose then YES, it could cause your problem. As I understand it, the running lights (brake & turn signals also) all operate independent of the 12v interior lighting. In other words, all lights needed for movement on the road are separate from all other 12v equipment. That little 4"x 4" box is only for the running lights AND a connection to charge the RV battery while connected to your tow vehicle. SO, if you have no running lights then it could be THAT ground wire. All grounds are common between both 12v systems.

The easiest way to test things is to buy an inexpensive test light at your local auto parts store. They run under $5. Connect the test light clip to the the POSITIVE (+) post of the RV battery and then use the pointed end to touchy various spots in the circuit(i.e. ground points). Tough the wires in that ground connection and at the end of the pigtail to going to the tow vehicle. If the test light fails to illuminate then look there for the problem.

I hope that makes sense to you. Electrical problems are usually simple to fix but hard to find.

Good luck,

Kevin

[H. John Kohl]

Andy,
Where is the Monty located? Trouble shooting past this point is going to take hands on.

Good luck.

[Andy]

Kevin thanks for the post, however I am kind of lost, but I do appreciate the post.

John, I'm at a friend’s house in lake Havasu City, AZ. I figured the RV repair guy would find the problem and I'd be a happy camper - Not! He kind of left it on me and I'm not sure what to do.

[trukdoc]

Electrical is easy. Most people let it confuse them and they make it hard. Take it one step at a time. Confirm power with a test light at EVERY step. Before a connector and immediately after a connector to confirm the connector is good. On to the next point. Assume nothing. I cannot tell you how many times it took to learn the lesson to not overlook anything. In Cars and trucks there is only one circut to trace, the hot as soon as you confirm the battery ground is good. On a trailer the ground can be the problem as well. When useing a test light, always make sure that the test lead is on the opposite lead than you are probing or it wont work. It takes a hot and a ground to make a circut complete. One more quick check, with the lights on, touch the lead of the test light to the truck and the probe to a metal surface, look closely, if the light glows in the least you have a ground problem. I am willing to bet with some patients a little common sense and MOC help you can figure it out.

[Andy]

Trukdoc, you make it seem simple enough, and I’d be happy to pick up a test light, I quite honestly just don’t know what to do with it once I have it. I hate to admit such ignorance. You say to confirm power before and after each connector. Do you mean each light? If you could be just a little more specific, I really hate announcing to the world how little I know.

[richfaa]

We lost our running lights.. Problem was a loose ground in that pin box as H John Suggested. Move things around in there and see what happens. I would redo that bare wire.

[BB_TX]

Andy - with your harness disconnected from the truck, you can put a jumper wire across pins 3 and 4 in the harness connector to apply power to the running lights from the camper 12 volts. See if they work off that power.
running lights from on board power