Ok guys/gals...Ive been having an issue when I hook up my travel trailer to my truck. The problem is that my running lights will not work when I turn on my lights. My blinkers work, hazards work, and my brake lights work but the running lights won't. So me and my neighbor tried to pin point the area the problem could be in. When I checked the 7 pin on the truck, it shows that it has power (12volts). When I hook up the trailer I would go under it to the junction box and start testing the wires. it is only about 5 foot from the truck to the junction box. Well there's no power. So we unhooked the plug from the truck, replaced it and still nothing. so we unhooked the plug again and we took the green wire (which is the running lights wire) and put it on the battery on the trailer.. guess what....the lights came on. Hooked the plug back up and nothing. Unhooked it again and put the green wire back on the battery and BINGO we got some lights. But when I hook it all back up it still want work. Well we Ohmed the wire to see if there was a break in the wire and it checked perfect....So now Imt lost. I was thinking about putting a toggle switch from the battery to the running lights so they will have work when I turn on the toggle switch...Does anyone have any other suggestions?

Somewhere between there you have power and where you have no power you will find your problem. More than likely in the plug or receptacle you will find a corroded or broken wire.

Try jumping oUt the top wires on the trailer plug itself....look it up on here ...I jump mine out to turn on my running lights when I am parked in a campground

donn0128 wrote:Somewhere between there you have power and where you have no power you will find your problem. More than likely in the plug or receptacle you will find a corroded or broken wire.Checked resistance in each of the wires from the plug to the junction box. They checked good. Its a very strange issue and I dont have a single problem with any of my other trailers.

prolandsurveyor wrote:Try jumping oUt the top wires on the trailer plug itself....look it up on here ...I jump mine out to turn on my running lights when I am parked in a campgroundWhat do you mean "jumping oUt the top wires on the trailer plug"? I put only the green wire on the plug and put a single wire on it to test the plug. The plug works (if that's what your talkiung about).

Are you sure about the colors? Yellow and green should be left and right turn signals. Brown should be running lights and white ground. Blue is for your brakes. The other two colors are for batteries usually the center pin of connector and back up lights on trailer. The first test should always be check your ground. Hope this helps.

Still having wiring issues on a Sunset Creek | Good Sam Community

Repoman1
Explorer
May 20, 2013
Finally got the female end changed and tested. It tested perfect. Gonna hook everything up tomorrow and make a pull to make sure all the lights are still working.
Repoman1
Explorer
May 20, 2013
I found the problem it was the female connector that the truck had a bad connection so i have replace to female adapter
sljkansas
Explorer
May 20, 2013
Check you truck plug wires and see if any wires have nicks in the insulation. Corrosion can get into the wire and you will see a voltage but the corrosion will add resistance and not pass enough current to power the lights. If you have a test light try it, it may work but it is a lower current draw than all you lights.

I had brake problems and it turned out to be a corroded wire under the truck.
leftybj
Explorer
May 20, 2013
It is hard to troubleshoot a problem without collecting the data myself but I will take a stab at it.

My guess would be that you have a bad connection on the truck side. If you check for 12V with a meter it will appear to be OK as the meter does not need much current to measure voltage. Maybe only microamps, depending upon the meter. The running lights require considerably more current to operate and the bad connection will not let this happen. It is like a garden hose that is pinched...you have line pressure (voltage) but there is no flow (current).

Retired Electrical Engineer
Repoman1
Explorer
May 20, 2013
handye9 wrote:
I've had same problem (flasher, brake, tail, and turn signal lights work / running lights do not) with three different truck and trailer combinations. The trucks were 03 Toyota Tundra, 06 Nissan Titan, and 08 Ford F250. All of them, had a blown fuse in the truck.

OP - Check the owners manual for your truck. In addition to your interior fuse box, you probably have another one, under the hood. There are seperate fuses for each of the trailer lighting systems. One of them operates running lights, only.

I've checked all the fuses the whole thing is I have power at the plug in female connector at the back of the truck but there's no power once I plug it in. so I'm fixing to head to the dealership
handye9
Explorer II
May 20, 2013
I've had same problem (flasher, brake, tail, and turn signal lights work / running lights do not) with three different truck and trailer combinations. The trucks were 03 Toyota Tundra, 06 Nissan Titan, and 08 Ford F250. All of them, had a blown fuse in the truck.

OP - Check the owners manual for your truck. In addition to your interior fuse box, you probably have another one, under the hood. There are seperate fuses for each of the trailer lighting systems. One of them operates running lights, only.
Repoman1
Explorer
May 20, 2013
Here is a link to youtube that shows you what the colors are and what they do. Go to the 1:16 spot.

http://www.youtube.com/user/etrailertv?v=p6_HhqbgexQ&feature=pyv&ad=5696436396&kw=7%20pin%20trailer%20wiring
Repoman1
Explorer
May 20, 2013
Rubber Ducky1 wrote:
Agwill has it right. The color code is as follows:
White: Ground
Yellow: Left turn
Green: Right turn
Brown: Taillights (& running lights)
OP you said you used GREEN wire to get your running lights on. That has me confused.

The diagram on the inside of the plug shows green as the running lights. And when I hook the green straight to the 12 volt battery all of the running lights come on.

Brown is a turn signal for this trailer and yellow is nothing. When I opened up the junction box the yellow was caped off from the factory with one of their close off ends.

Im going to go to a local dealer tomorrow that sold me the plug. But also its strange that when I put the green to a power source all of the running lights come on like they should. How would you explain that?
SprinklerMan
Explorer
May 20, 2013
take a 12 v battery , hook a ground wire up to the frame , go to a side marker light and take the positive wire and run a jumper to the hot on the side marker . All the running lights should be on when you do this . Now go to the junction box and search for a hot wire , that will be your feed for the running lights . Odds are there is a grounded out wire somewhere on the line . Now if it all works straight off a battery , put a 5 amp fusable link in line on the hot and see if it blows . This will help narrow down the problem .
Rubber_Ducky1
Explorer
May 19, 2013
Agwill has it right. The color code is as follows:
White: Ground
Yellow: Left turn
Green: Right turn
Brown: Taillights (& running lights)
OP you said you used GREEN wire to get your running lights on. That has me confused.

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Still having wiring issues on a Sunset Creek

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