Who makes a GOOD 4-pin installable plug?

Not really. It took about 4 hours to rewire the trailer. This time I took precautions in the hopes of not encountering this disappearing wire problem for a THIRD time. I was hoping to "ice the cake" as it were with a quality connector instead of having to resort to the same old junk that failed on me twice already and not have to spend the 20 minutes, ever.

I’ve never seen a 4 flat connector like you’re looking for.
Either use an adapter from a different style plug so you can use “your” wire all the way to the plug or just crimp on a connector and call it a day. What’s it take, like 20 min to put a new one on when the old one corrodes out?

mkirsch wrote:
All the vehicles I plan to use to two this trailer have 4-pin, but not all have 7-pin, and they're not all my vehicles so I can't demand they change plug types.

You can always wire a 7-pin and build/buy an adapter (which stays out of the weather most of the time) for the other vehicles.

I would mount a weather proof junction box on the front of the frame, then use the standard four pin harness from there to TV.
Make sure you coat all connections with a electric de-oxidation grease. I put it inside the connectors prior to crimping.

It's the trailer wiring that was gone. No problems on the vehicle side. The trailer wiring was just plain rotted away, nothing left but copper sulfate and insulation.

I had no choice but to rewire the trailer from scratch. That is precisely why I was looking for a good 4-pin plug that could be installed on my new wiring like you can with a 7-pin Pollack plug.

This time I used all quality marine grade 16ga wire. Wasn't cheap, but it is nice stuff to work with, much better than the "primary wire" you get at the auto parts store.

Unfortunately I still haven't found a good 4-pin plug. All the vehicles I plan to use to two this trailer have 4-pin, but not all have 7-pin, and they're not all my vehicles so I can't demand they change plug types.

In the meantime I had to tow the trailer so I ended up using a cheap 4-pin plug from Walmart, and more heat shrink butt connectors.

Here is one made by Wesbar available at ETrailer.

After seeing it, I may change out my 4pin connector on my cargo trailer.

I also installed this 7pin/4pin on my truck.

There might be more going on than you know...is my guess

Copper is a good corrosion resistance material...Copper corrodes at negligible rates in unpolluted air, water, and deaerated nonoxidizing acids.

But it does absorb acid to rot itself...why most places has that comment 'unpolluted aire, water...etc'...SMOG is acidic and when mixed with H2O, creates an acidic condition

Then a possible galvanic condition with 'that' vehicle. GM found out the hard way with the then new OATs coolant and one of the new ways to check coolant condition was to use a digital multi meter to measure voltage in the coolant (galvanic action....AKA a battery)

Your profile says you live in Rochester NY (loved going there for business meeting with the East Bay guys and West Bay guys and staying at the Woodcliff Lodge) Rats...just checked...the old buildings have been replaced...

Anyway, back on your topic...there are tons of folks in New York who have similar trailer connectors. Many have Scotchlok and have not reported the level of corrosion you report...flaky connections yes, but not corrosion of this level

Am assuming your corrosion issue is at the trailer side of the connectors, right?

If so, suggest checking the trailer wiring and making sure the grounding is solid...and/or rewire in a new heavy gauge grounding system

Good luck

mkirsch wrote:
Thanks, but even though that looks like a high quality cable, it introduces 8 additional crimp connections that I could avoid by simply having a quality plug to install on the ends of the new wires.

What failed were the CONNECTIONS, not the plug. Anywhere there was a butt splice in the wire, the wire disintegrated. I used heat shrink sealed butt splices too. The wire was literally GONE for as far back as I peeled the insulation, replaced with a blue powder. I don't know how you could possibly prevent that with "maintenance."

This is why I want to avoid butt splices wherever I can.

Sounds like a wire defect or contamination. I have never had any issue with a butt-splice sealed with heat shrink. I have at least six that are frequently submerged and holding up for over a decade powering a sump pump. At least 12 years for the ones connecting my in-bed 7 pin connector and they are exposed under the truck.

Install a junction box on the tongue. Then wire both 7 and 4 pin leads to it. That will cover 99.9% of tow vehicles without an adapter. In the future if you need to replace a lead, it's easy.

Thanks, but even though that looks like a high quality cable, it introduces 8 additional crimp connections that I could avoid by simply having a quality plug to install on the ends of the new wires.

What failed were the CONNECTIONS, not the plug. Anywhere there was a butt splice in the wire, the wire disintegrated. I used heat shrink sealed butt splices too. The wire was literally GONE for as far back as I peeled the insulation, replaced with a blue powder. I don't know how you could possibly prevent that with "maintenance."

This is why I want to avoid butt splices wherever I can.