Trailer lights issue - RT Turn signal out due to sacrificial oxidation known as “copper rot” How to prevent it?

[Don2222]

Hello
The right turn signal failed on my trailer, it would not blink. All the wire insulated butt connections with heat shrink ends were very good! So I finally traced it down to the 16 guage green trailer wire that goes to the right turn signal, which the stranded copper wire was very brittle and contained a white substance inside the wire jacket! It suffered from sacrificial oxidation, commonly known as “copper rot”!! Budget wire harnesses use untinned copper and porous insulation, allowing capillary action to wick road salt and water! I went crazy and spent $16.99 for a new light assembly and $3.99 for new 10 pack of insulated Butt connectors with heat shrink ends before I found the real issue! I tested the old light assembly still work fine! The harness and lights and connectors were all purchased at Harbor Freight. When I installed the HF wire harness on my trailer I made a big looop of extra wire with a wire tie on it just before the tail light so I had to cut it back a lot when reconnecting it and it worked!!
Also you can see in my pic above that I ran the white ground wire to a black wire with a round connector on it to the trailer frame with a stainless steel screw that fights the rusting. Before I screwed it in, I wire wheeled the chassis to remove all the paint for the very best ground connection.
See bench test pics of old HF Tail Light below
How can we prevent this in our trailer harness wiring??

 

[Whitenuckler]

Hello
The right turn signal failed on my trailer, it would not blink. All the wire insulated butt connections with heat shrink ends were very good! So I finally traced it down to the 16 guage green trailer wire that goes to the right turn signal, which the stranded copper wire was very brittle and contained a white substance inside the wire jacket! It suffered from sacrificial oxidation, commonly known as “copper rot”!! Budget wire harnesses use untinned copper and porous insulation, allowing capillary action to wick road salt and water! I went crazy and spent $16.99 for a new light assembly and $3.99 for new 10 pack of insulated Butt connectors with heat shrink ends before I found the real issue! I tested the old light assembly still work fine! The harness and lights and connectors were all purchased at Harbor Freight
How can we prevent this in our trailer harness wiring??

Maybe it was "Soy" insulation and the cheapest they could use. If you can run it in flex away from the sun it will last.

 

[Don2222]

Hello Whitenucler
Would this HF protective wrap help?

 

[EatenByLimestone]

It’s hard to beat a good solder and flux with heat shrink around it. Even an ugly solder job keeps the air and water out of the joint!

 

[EatenByLimestone]

Hello Whitenucler
Would this HF protective wrap help?

Maybe for a road only trailer. A boat trailer will still get water in the joints. It may help if abrasion is an issue though.

 

[Whitenuckler]

Hello Whitenucler
Would this HF protective wrap help?

Hello Whitenucler
Would this HF protective wrap help?

It would help for sure. It would protect the wires from the sun, and also perhaps from damage. I bought a new trailer this year and the wiring is protected underneath. You can also get a tape type wrap for the ends, This is commonly used in car harnesses. I used some on a pellet stove wiring addition.

 

[begreen]

It’s hard to beat a good solder and flux with heat shrink around it. Even an ugly solder job keeps the air and water out of the joint!

That's the way I wired up two sailing yachts. They are still going strong after 30 yrs. Use marine shink tubing. It encases the solder joint in a waterproof glue under the shrink tubing jacket.

 

[Don2222]

It would help for sure. It would protect the wires from the sun, and also perhaps from damage. I bought a new trailer this year and the wiring is protected underneath. You can also get a tape type wrap for the ends, This is commonly used in car harnesses. I used some on a pellet stove wiring addition.

Hi Whitenucler
What does the tape type wrap look like?
Like this?

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