Trailer wiring problems

B Gillespie · Dec 22, 2008

I am rewiring my car hauler and having difficulties. I replaced the axles with a new set of 3500# axles with electric brakes on both. The brakes operate magnetically therefore it is not necessary to differentiate positive or negative. I used seven conductor trailer wire and grounded the trailer to the frame with the ground in the wiring harness in four places. I do not have a trailer brake controller in my P Wagon and it is the only vehicle I have hooked to the trailer. After I finished the wiring, I hooked the trailer to the truck and all lights functioned properly. I got in the truck to pull the trailer out of the garage, applied the vehicle brakes to shift out of park, and all lights on the trailer stopped working. The brakes on the trailer also locked up. Wiring runs down pass. side of trailer, then loops around ending at the driver side stop/12V outlet/ground/license plate light area.

Here is my lovely retard sketch of the trailer:

trailer%20wiring%20retard%20sketch.bmp.jpg

Green=ground
Purple=12V cig. lighter and license plate light
Red=Stop
Grey=Reverse
Yellow=Amber running light

Any ideas why nothing works? laughing1

blacksheep10 · Dec 22, 2008

weird ground issue?

87yjtoy · Dec 22, 2008

04 P wagon? LED lites on the trailer? Read something about this combo not being compatible, Cant remember exactly what it ws though. Call dodge dealer & get the correct harness & flasher assembly. I think . edit can probably get the right stuff at a good trailer place.

caglezxj · Dec 22, 2008

sounds like a ground issue with the lights going out, and you wouldn't think it would be with the brakes coming on. But if you feed power on something that is wired in series and doesn't have the ground on right it will make everything light up different. Besides your grounding wire through the harness is the ball rusty at all? I have seen sometimes that it will not make a good ground through the ball. My 08 Tundra will not light the brakes up on my trailer unless I am hooked up to the ball and it has good connection. The light on my brake controller will not come on either. Double check that you have the right harness for your application as stated above.

Caddishack18 · Dec 22, 2008

You got something goofed up! Bring it to a professional.

Caddishack18 · Dec 22, 2008

6 plug or 7 plug? What year of P wagon? Factory harness on the wagon? Sounds like you have a ground problem. the brakes are getting power from another source, either the headlights or the accy wire in the truck plug.

87yjtoy · Dec 22, 2008

which wires are hooked up to the brakes? The brake signal wire has to be wired seperately thru the trailer connector to the brake controller in the truck. it cant go thru the brake light wire. Your diagram doesnt show it that way but that is the only way the brakes can activate. I also run the other wire from the axle directly thru the trailer connector & grd that wire to the truck.

draggbody · Dec 22, 2008

the brakes should use a blue wire at the 5 oclock position... here is a diagram... make sure EVERYTHING that should use a ground, make it go to ground... they will work eithr way, but make life easy on yourself... here is a diagram to help....

http://www.farmbox.com/images/7WayTrailerEnd.jpg

Caddishack18 · Dec 22, 2008

actually a pretty good diagram. They are using a car trailer/ stock trailer color code on a camper plug. the black and white wire could be switched

B Gillespie · Dec 23, 2008

Grounded through the ground wire on the trailer wiring harness/truck wiring harness.

7 wire harness, 7 pin plug

Yes, the brakes are getting power through something, as I have not installed the trailer brake controller yet.

I need to check the truck wiring, I think this could be the issue. The wiring diagram posted is different than what I used:

Caddishack18 · Dec 23, 2008

thats a stard RV color code. It right if you used green as your trim lights. Factory harness on the power wagon?

B Gillespie · Dec 23, 2008

Caddishack18 said:
thats a stard RV color code. It right if you used green as your trim lights. Factory harness on the power wagon?

All factory wiring on the truck.

Caddishack18 · Dec 24, 2008

Fix it yet???

B Gillespie · Dec 26, 2008

About to start! Christmas family stuff slowed down errthang round here.

onealdodge · Dec 26, 2008

Bryan I will get u one if we need it.I'll send it to u with the emblem....let me know!

B Gillespie · Dec 27, 2008

Got it! There were problems in the plug as Brian had suggested. Checked all of the lights and the 12 volt plug, all working great.

Thanks for the help Steven. I found a harness at a trailer place here in Columbia.

The new Prodigy P3 is sweet!