Best way to ground tail and marker lights

[Bears]

Hey guys,

I recently bought a 1974 Boler and decided the rats nest of wiring had to go. My first priority is to update my tail and marker lights to the LED options available through Princess Auto. I've found a ton of great info on these forums but I've yet to find any advice on grounding.

I'm running the 4 pin hitch connection. Is a ground from the hitch connection to the trailer tongue enough? Do I need to ground each light separately as well? Is a stainless steel bolt which connects the tail lights a sufficient? Any advice would be greatly appreciated.

A diagram would be so helpful.

[AC0GV]

Originally Posted by Bears

Hey guys,

I'm running the 4 pin hitch connection. Is a ground from the hitch connection to the trailer tongue enough? Do I need to ground each light separately as well? Is a stainless steel bolt which connects the tail lights a sufficient? Any advice would be greatly appreciated.
A diagram would be so helpful.

Always run a negative wire all the way to each light . Your lights are not mounted on the frame and need the wire run all the way to the light

A Scamp diagram should be about the same as any other RV. WHite, brown, green and red for DOT required lights in this print.

[Bears]

Should all my cascading negative wires just run directly back to my 4 pin harness or should there be a splice at some point which makes connection to the actual frame of the trailer?

[David Tilston]

Originally Posted by Bears

Should all my cascading negative wires just run directly back to my 4 pin harness or should there be a splice at some point which makes connection to the actual frame of the trailer?

I see no reason to ground 12VDC to the frame. Just run your negative to each light and splice the three wire ends as you see fit, (I'm a nut on this one). Or splice into the wire, without cutting it:

https://www.youtube.com/watch?v=DuZWfQxe6D4

I would use liquid electrical tape here.

[gordon2]

Originally Posted by David Tilston

I see no reason to ground 12VDC to the frame. ...

I agree.. Scamp uses the trailer frame for brakes ground (neg).. and I have seen that cause the brakes to fail to work when the connection to the frame corroded as it will do. I rewired my brakes so there is real wire going to them.

So you connect your neg from tow veh. through the 4 or 7 pin to a buss bar in the trailer. Never rely on the hitch ball for an electrical connection. Then run wires from the neg buss bar to the various lights, brakes, ect. Also the neg wire from the trailer's battery connects to the buss bar. You dont need a seperate neg wire to each and every thing.. you can daisy chain them (aka series connection) if its easier (subject to the wire size being sufficient for the current) using various connectors. If you have brakes, I would run a separate wire from the neg buss bar to the left and also right brakes. At the very least, run a wire from the buss bar to one brake then from there to the other brake. Just dont run from light to light to brakes or something like that.

[AC0GV]

I would use liquid electrical tape here.[/QUOTE]
Yes, that tape joint is not weather proof and wire will turn green. also never break tape like that video, always cut it from the roll.

[Bears]

This is exactly the explanation I needed! Thanks so much. I'll let you know how it goes.

[floyd]

Originally Posted by Bears

Should all my cascading negative wires just run directly back to my 4 pin harness or should there be a splice at some point which makes connection to the actual frame of the trailer?

A 4-pin trailer wiring kit is a 4 lead harness already color coded


Brown...Tail/running lights
Green... Right turn
Yellow... Left turn
White.... Ground.


Run the harness all the way back to the plug including the Ground.

[Darwin Maring]

Me, I run the ground wires to the frame.

[floyd]

Originally Posted by Darwin Maring

Me, I run the ground wires to the frame.

For the few pennies worth of wire saved, you sacrifice having a discreet wiring harness with all connectors and ground points protected from outside exposure to corrosion and the elements and all tucked inside the body of the trailer.
There simply is no advantage in this application (fiberglass bodied trailer) to using the frame for grounding DOT wiring.

[David Tilston]

Originally Posted by Darwin Maring

Me, I run the ground wires to the frame.

If you are talking AC, I don't see a problem with that. The reason 120VAC should be grounded to the frame is to help prevent electrocution. If exposed metal is grounded, than it can’t be energized at 120VAC.

12VDC is not likely to kill anyone, but connecting the battery negative to the frame won't cause a problem. This is done on cars all the time. It just should not be depended on as a conductor.

[gordon2]

Failed brake ground (neg) connection to frame. Brakes did not work.

[Borden]

Originally Posted by gordon2

I agree.. Scamp uses the trailer frame for brakes ground (neg).. and I have seen that cause the brakes to fail to work when the connection to the frame corroded as it will do. I rewired my brakes so there is real wire going to them.

Well said gordon2 and floyd: Have seen these problems on our old smaller utility trailer wire saving is not worth the potential problems.

We have our bolers whole system with dedicated ground and the 7 pin wire plug will accommodate all of our needs.