Crazy trailer light problem

[Shellback]

So I have a small galvanized trailer that I used for putting my slide in camper in and out of my garage. Sold the camper and now use the trailer for a little 14 footer. It has LED lights andthey always worked fine. My brother is borrowing the boat to take to Florida, so he came up yesterday to take it for a test run. Hook up the lights and only 1 tail light was flashing dull with the four ways on. Took a test light, grounded it to the frame and then probed the tail light not working. Both tail lights started flashing normally. Knew I had a ground problem. Re did the harness to ground at the coupler, no change at the tail lights, but did test properly at the tongue. Probed wiring where it branches out to each frame member after the tongue. No go there with the test light grounded to the tongue where it splits to each frame member. Move the ground up to the jack frame on the tongue and get power to the lights. What the heck? Grounding to the frame at the jack frame and everything works, ground to the galvanized frame 20 inches away, and it doesn't work? The frame sections are all bolted together and the tongue is one piece. Rather than wasting a lot time, I just made up a couple jumpers, drilled the tongue and side frames, then used the jumper wires to insure a ground between frame members. Everything now worked. Not sure how the frame had lost ground continuity. Does galvanizing not conduct electricity?























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[Huntindave]

Originally Posted by Shellback

Does galvanizing not conduct electricity? /?

I think you already proved the answer. Galvanizing breaks down over time resulting in a surface coating which has a high electrical resistance.

"The galvanization process involves applying a zinc coating to the surface of ferrous metals to retard or prevent the corrosion of the substrate metal. A zinc coating produces a physical barrier while also working as a sacrificial anode. When zinc reacts with atmospheric oxygen, zinc oxide is produced, which forms zinc hydroxide in the presence of moisture. The zinc hydroxide further reacts with carbon dioxide in the natural environment, resulting in a thin layer of impermeable zinc carbonate, which binds to the zinc beneath. Zinc carbonate thus protects and preserves the zinc layer from any further corrosive oxidation."

The most effective way to avoid "ground" issues on any trailer (regardless of construction) is to run a dedicated ground wire from each light all the way to the trailer plug. Bypassing the frame entirely will eliminate or at the very least greatly reduce many trailer light issues.

[REW]

As you and Huntiing point out - run a dedicated ground wire to every light fixture that is on your trailer.

Do NOT relay on the trailer frame for a good reliable ground.

By the way, if you wanted to use the galvanized frame, you just have to take a sander to grinder to grind the surface of the metal - where the ground is picked up and attach a terminal connector with a machine screw to the frame. Before you do the attachment, slather a good amount of grease on the terminal and the final bolt after being made tight. The grease will provide moisture and oxygen rejection and help to avoid future ground issues.

The older galvanized has not rusted but it has become oxidized which for many folks is completely non conductive.

Take care