All Trucks, Campers, Trailers, RV's and Motor Homes - trailer wiring

I'm trying to get my son's boat trailer wiring working and have come to a dead end.

I've checked the continuity from the trailer plug to each light socket on the trailer,even changed out the bulbs. Everything seems to be o.k. there

Checked the towing truck plug. I confirmed that is o.k. by hooking up a different trailer, and that trailer's lights work.

Anybody have any suggestions?

Thanks

you most likely do not have a ground, add a ground from the engine to the light connector, then from the boat side to each light. don't rely on the hitch for ground. that is the most common cause of no lights.

life begins when the kids leave home and the dog dies

my thoughts initially were of a ground,however in both tests with the two trailers ,the trailer tongues were not hitched to the truck in either test.
Its probably some simple thing that i have missed.

If the truck and trailer were not hitched, you definitely would not have a ground through the hitch. Check for the ground wire on the trailer plug. should be bolted to the trailer frame. Check it for continuity. Do the same on the truck connector.
I agree with speedwrench. You have power to the lights, but need the ground connector to complete the circuit.

Thanks speedwrench and goldstar. I'll connect the trailer to the truck hitch this week-end.

daswede

:wall: O.K.

Well,i guess i'm ready to install a new wiring kit on the trailer. have spent too much time on this issue.
I'm pretty handy and would like some advanced words of wisdom before i start. I don't have a kit in mind other than maybe it shroud be a submersible 4 pin one.
Thanks,
daswede

Keep everything tied up tight to the trailer so it don't hang. Every splice you make, seal it with a squirt of dielectric (sp?) grease in the connector. Same for the ground when you bolt it to the frame. I'm going through this right now with another boat trailer I'm fixing up. Oh yeah, and if you can spring for a set of submersible LED tail lights, you'll never want anything else.

I think you are still having problems with the ground. There should be a white wire in your 4 pin connector that goes from the connector to some bolt probably on your trailer tounge. Check for continuity between the 4 pin connector and a "bare spot" on your trailer frame. If this test shows continuity, then the frame is grounded to the plug. How many light assemblys do you have? If its just the 2 turn/stop/running on the back of the trailer it is possible that the grounds are bad on both of them. The bolts that hold the assembly to the trailer are the "ground" for whole assembly and all the bulbs that are inside. There are usually "keeper nuts" that try to "bite" into the frame that are supposed to make the ground connection. However, these connections are NOTORIOUS for becoming corroded and not allowing the ground connection to happen. (I have about 6 trailers between work/home/friends/scouts that I work on on whenever they don't work) If you still want to rewire the whole trailer, submersible LED's are the way to go. The best ones will have a seperate ground wire that you can use to make a solid connection all the way back to your 4 pin connector. Instead of relying on the frame and "keeper nuts" to complete your ground path, you have a dedicated wire to do so. Make your splices with "waterproof" wire nuts. They are kinda expensive, but well worth it. Also wrap your splices with electrical tape, it helps prevent wire splices from being pulled apart if a wire gets accidentially snagged. If you get a set of lights (LED or otherwise) that use the frame for ground, expect to have the same problem in the future. Ground problems are THE #1 issue I have with keeping trailer lights working.

I went all over the wiring again. Checked each, and every wire,nut,bolt for ground. Applied dielectric grease to connectors,points of contact. Rang out the elctrical wiring again.
As of now,i suspect the truck wiring and/or connector and
suggested to the owner to try another trailer,or two, and see if they work.
In the mean time i bought one of those light tester pencil thingys.
New submersible lights are on the list to as the trailer is 20 yrs. old.

Thanks

Follow-up:D

Sorry for taking so long to get back to this issue,but have more pressing things to do.

I probed the truck hitch wiring and the connector pins were OPEN. I crawled under the bumper,and lo,and behold there were several wires that were just hanging. I replaced the 4 pin and the round connector as a unit. Voilà!! Trailer has lights.
My bad for not checking the truck wiring to.

Thanks to all for your help.

daswede.