Thanks for all the replies. In answer to all the questions:
I have the OEM 7 pin round connector on my 4Runner. That goes to the 4 pin plug for the wires. The trailer has a removable coupler and came with a segment of the wire that is about 6 feet long and connects to the rest of the trailer wires with another 4 pin connector.
The ground is through the trailer frame and that is frequently a problem. The screws that go into the frame rust and I loose the connection. The other issue is corrosion at the 3 connections: 7 pin plug on the 4Runner. (See picture), 4 pin connector to the 6 foot wire, 6 foot wire to the trailer wire.
BTW this is on a 30 yr old trailer. The 7 pin connector in the picture is maybe 3 years old.
I'm putting on new tail/turn signals. I plan on getting LED maybe Linkitom or Wesbar brands. For the connections I will use the liquid tape that Mike and gm280 suggested as well and maybe shrink tubing over that.
I did soak that 7 pin connector as well as the other connectors in CLR and that cleaned them up. In the future I'll try Tassie's method and spray with WD40 after *every* outing. Is there a better method
4 pin connectors have no place in a saltwater environment not to mention the science experiment in dissimilar metals you described.
Saltwater corrosion is the result of stray currents interacting at the molecular level with the various elements that make up the metals in the system. Once it starts at one location, it quickly progresses throughout the entire system.
The trick is to minimize the use of dissimilar metals, maintain good ground paths and make sure all connections are keep dry or water proofed
It all starts with a quality
7 pin connector pig tail. You wanted one with plated pins. Preferably nickel. Copper pins with be green and corroding in a week.
From there I go to a
water proof termination box mounted on the tongue. Makes a convenient location to terminate the wiring between the truck and the trailer. Also provides “test points” if the need to trouble shoot the system arises.
Don’t use the cheap trailer wiring harness sold with many of the light sets. I run a good quality marine rated
18/2 duplex wire between the junction box and the various components.
Use nothing
adhesive lined butt connectors to attach the components to the wiring harness. If you want to go one step further, although not needed, you can cover the butt connectors with second layer of
adhesive lined heat shrink tubing.
Since this is a family forum, I will not voice my real opinion on the use of liquid electrical tape. Lets just say it’s a band aide at best....
Normally I run duplex wire to each component to provide a dedicated ground. If that’s not in the cards, the next best solution is to install a stainless ground stud.
Drill and tap a 10-32 UNC hole in an area with access to both sides. Apply thread locker (seals threads) and thread a stainless steel screw into the hole and allow to protrude roughly a 1/2”.
Apply thread locker to a stainless nut and thread that on the screw and tighten. Coat the head of screw and circumference of nut with RTV and let dry.
Use a multi-meter to check the resistance between your new ground stud and the 7 pin connector. Ideally there should be 0 ohms between the two points. Should be a 1/2 ohm or less.
I like
Optronics (LED lights). The quality of the hardware and wires are better than most
