Trailer Lighting

[Toytaco2]

My build is to the point now that I am connecting up the final wiring for my trailer tail lights and side clearance markers and I'm hoping that all our wiring gurus can lend me some advice or at least set me straight before I do something wrong.

I notice that most of the threads I've read talk about grounding the trailer frame, I assume using the ground lead off the "4 wire flat connector". Is there anything wrong with extending that white ground wire around the trailer and connecting the lighting ground leads to it INSTEAD of to the frame? Is there some reason that the frame needs to be grounded that I am unaware of?

[Rock]

No issue. My camper is wood so I'll have to run wires to each individual lamp.

I can't see any reason to ground the actual trailer frame to the vehicle electical system, but I guess you could ground the frame at one point with the white wire if you want to. Would prevent a potential static charge buildup between vehicle and trailer?

Properly made wire connections are typically going to be a much better ground than the frame due to the inevitable corrosion issues on a steel or aluminum frame.

Eric

[cleonard]

Another vote for using wire for the ground and not relying on the frame.

However, I would connect it at one point. Preferable in a spot that will not get wet, or if it does get wet it will quickly dry. It's not that much of an effort to connect the ground wire to the frame and then should you need it later it will be there.

[bobhenry]

90 % of all trailer lighting and wiring problems are from lousey grounding. Tail light and clearance lights all blink with the turn signals are activated or things just plain don't work. By all means run a dedicated ground to all of your 12 volt fixtures and hard wire them back to that all important white wire going back to the tow vehicle ground. I ran dedicated grounds to my ac fixtures as well so they will work with their GFI protection without a dedicated ground on the ac side GFI fixtures are totally worthless.

I chose to seperate my 12 volt tow lighting from the 12 volt convenience items in my trailer. The on board battery powers all the convenience items while the tow vehicle handles only the required tow lighting.

[Senior Ninja]

Just a thought. While you are doing the wiring use the plastic covering around all the wires I think they're called looms? I bought mine at HF two of them were just the right length for the 4x8 trailer they sell. No worries about chaffing through the insulation now.
Steve

[firemaniac]

The reason for the White ground wire on the connector is to ground the trailer to the tow vehicle. The reason for that is in most cases the Stop, Turn, and Tail lights are powered from the tow vehicle and grounded to the trailer frame. Therefor the ground wire attached to the frame is there to insure a complete circuit back to the tow vehicle.

The trailer battery is also grounded to the frame, and if you have or will equip the trailer to be charged from the tow vehicle the White ground wire will need to be appropriately sized.

[Senior Ninja]

What BobHenry said!
What Firemaniac said!
I did exactly as they said.
Steve

[dmckruit]

The trailer lights are grounded through the bolt that attaches to the metal frame. So if you are relocating the lights to attach to wood, or painted metal, they probably won't work. I found this out when I needed to use my in progress trailer to get my aluminum sheet. I jerry rigged my lights to the wood fenders with masonite, and spent a few hours trying to figure out why they didn't work. Then I realized that the ground was through the bolt. I ran scrap wiring from the ground bolts to the white ground wire of the vehicle connection and everything lit up like a christmas tree.

[madjack]

...screw the frame ground...run a dedicated ground to all brake/signal/signal lights...lot less hassles now and in the future...what bobhenry said is right on the money.............
madjack

[Von Pook]

I have had several trailers through the years, and found that if I just went ahead an ran a "ground" wire to the lamps, then they always worked. The frame style "ground" is very prone to failing when an officer is behind you.

[chorizon]

OK. I definitely plan to run 2 wires to all of my trailer lights. But if I also ground to the frame, what about the AC ground to frame on the trailer. I know its been discussed before, but I still don't understand if its OK to ground the AC and DC circuits to the frame.