Need help re-wiring my trailer!

[kamby]

Re: Need help re-wiring my trailer!

When I have the headlights on and apply the brakes, all the lights on my trailer go out.

You may have a weak ground problem. A poor ground that is strong enough to provide some lighting functions but not all. When the taillights and brake lights are used at the same time, it creates the maximum amp load of the lights on the trailer. If a ground problem exists, it will show at this point. The places to check grounds are as follows.

The connector on the tow vehicle should have a ground wire secured tightly to a clean unpainted surface on the frame. A wire attached to an insulated body sheet metal panel, a surface with undercoating or rust can cause a ground problem. Test with an ohm meter for the path of least resistance. (battery disconnected from vehicle)
The t-connector from the tow vehicle should have a ground wire and should be secured tightly to a clean surface on the trailer.
Each tail lamp assembly at the back of the trailer also must be grounded. This is done in one of two ways. The first is by a separate wire coming from the back of each taillight lamp assembly being secured to the frame. The second, and most popular, ground is achieved through the bolts of the taillight lamp assembly. In this case, the lamp housing must be attached to the metal frame of the trailer. If the lights are mounted on wood or plastic material, the light circuit will never receive a ground.
Note: The trailer hitch ball of the tow vehicle should never be considered sufficient ground.


When I use one turn signal the other one blinks.

This is usually related to one of two things. The first could be a short somewhere in the system. All trailer wiring and the tow vehicle connector should be checked and tested. The second, which is the most common problem, is a weak ground in the system.

Should I unplug my boat trailer when I back my boat into the water?

Yes. You should always unplug your boat trailer when backing into the water. When the trailer lights are submersed in water, it can create a short causing the vehicle fuses to blow and / or result in damage to your vehicle or wire harness.

I am blowing fuses / circuit breakers on my tow vehicle.

Possible live wire shorting to ground. Check all wires for bare copper or places where a wire or cable could be pinched. Possible overload of too many lights on the trailer. Calculate the amp load your trailer is pulling, see below. Most cars are equipped to handle only standard lighting on trailers; one rear turn / brake signal on each side and 1 set of left and right marker lights. Large trucks, vans or suvs can handle more. Check your owners manual.

If you know the wattage of the bulbs on your trailer you can use the formula P = I X E

P = watts
I = amps
E = 12 (volts)

NOTE: For estimating use only. Amperage is rounded to the nearest whole value. May not apply in all cases. Always check with your tow vehicles owners manual about adding additional loads to your electrical system. Some 12 volt batteries produce up to 14 volts on full charge. Use a VOM (volt ohm meter) to test.

See if there is another bolt nearby to ground onto besides the coupler bolt, problem with those is if the trailer is painted or rusted underneath the couple your not gonna get a good ground.

Since you have a white wire running out of the tail lights (kinda odd but i have seen them) run a ground wire from the plug straight to the white wire then to the other white wire and then to some where on the frame or the mounting nut for the tail lights to ground the trailer and the side marker lights.

Or mount the white wire to the frame and the white wires from the lights to the frame remember scrape, may even want to use some diaelectric grease to save off rusting for a while. Odds are if your lights have ground wires there not gonna ground through the posts, these lighs were typically used on wooden trailer bodies and campers.

This is a long post but so much useful information some i didnt even know i did low voltage wiring for a few years (datacom/telephone, coax etc) you cant blame him for wanting the most info out of everyone..

 

[thepotroast]

Re: Need help re-wiring my trailer!

Did you get the lights working properly yet??

 

[Biggems]

Re: Need help re-wiring my trailer!

Haven't gotten the chance to go back out there yet. It's raining here today. Hopefully at some point this weekend I'll get the chance to!

 

[Biggems]

Re: Need help re-wiring my trailer!

Ok good news everybody, the ordeal is over! You all were right, it was just a grounding problem.

I scraped some paint and rust off of the tongue of the trailer, crimped a round metal connector to the ground wire and touched it to the freshly scraped metal. It worked! I don't have a drill so I wasn't able to permanently mount it. I'll do this soon as I get a hold of my buddy with a drill. I also took the bolts off of the rear mounting brackets where the other ground wires were and scraped the paint off and re-attached.

Sorry this took so long, problem is my boat is far away so I only get to go out there once or twice a week.

Thanks everybody! Hopefully this forum will be useful to others in the future.

 

[kamby]

Re: Need help re-wiring my trailer!

Ok good news everybody, the ordeal is over! You all were right, it was just a grounding problem.

I scraped some paint and rust off of the tongue of the trailer, crimped a round metal connector to the ground wire and touched it to the freshly scraped metal. It worked! I don't have a drill so I wasn't able to permanently mount it. I'll do this soon as I get a hold of my buddy with a drill. I also took the bolts off of the rear mounting brackets where the other ground wires were and scraped the paint off and re-attached.

Sorry this took so long, problem is my boat is far away so I only get to go out there once or twice a week.

Thanks everybody! Hopefully this forum will be useful to others in the future.

Congratulations glad you got the lights working properly. You will find a lot of helpful people on this site with many many years of experiance behind there belt. Now get some fishing done