Trailer Wiring

[Drahcir495]

What should I look at to get the vehicle side connector for hooking up to a trailer harness? I’ve been on Amazon looking and found a few, but most are both the trailer and vehicle side. But they are 4 pin or 5 pin connectors. What is the most universal one? 

[gogmorgo]

I’m sure there’s an application for a 5-pin trailer connector but I don’t know what it is. I’ve never bothered trying to find out. You won’t encounter it much other than store shelves. 
Four-pin is common and easy to hook up on a Comanche because brake and turn signals are combined. But the connectors kinda suck, they’re small and easy to break the wires off. Plus the connector pins are very easily damaged and generally prone to corrosion. But it’s all you need to connect to a uhaul, small trailers without brakes, or trailers with surge brakes like most boat trailers. 

I’d go with a seven-blade myself. Just as common as the four-pin if not more so, and much more reliable, plus it opens up the option to charge trailer batteries and run electric trailer brakes, reverse lights on the trailer should you so desire… although those two features mean more complexity to hook up. But you wouldn’t need to if you didnt specifically want them. You can adapt it down to four-pin if you need to with an off-the-shelf adapter, or better yet get a 7-blade and 4-pin combo like this:

 

The only challenge is finding somewhere to put one. I’ve seen license plate lights replaced with it on the MJ, it’s also common to hang a bracket (the socket often comes with one) down below the bumper or trailer hitch crossbar. 
 

But I guess what will work best for you is going to depend on what you’re doing with it. 

[fiatslug87]

I believe the 5-pin accommodates reverse lights (as does the 7-pin) while the 4-pin does not.

[jpnjake]

16 hours ago, Drahcir495 said:

What should I look at to get the vehicle side connector for hooking up to a trailer harness? I’ve been on Amazon looking and found a few, but most are both the trailer and vehicle side. But they are 4 pin or 5 pin connectors. What is the most universal one? 

99% of the time it’ll be a 4 pin or a 7 pin connector, a 7 pin requires a decent amount of extra wiring, including a brake controller, 12v supply and reverse. And I will suggest running the marker lights and possibly the turn signals on a relay with a new larger wire carrying the load, I’ve run into problems on trailers with too many lights for my stock wires that blow my fuses. This is mainly a problem on larger enclosed trailers. 

[Drahcir495]

That dual connector is very cool. Thank you for all the advice . I’m leaning towards the 4 pin connector. 

[gogmorgo]

7 hours ago, jpnjake said:

99% of the time it’ll be a 4 pin or a 7 pin connector, a 7 pin requires a decent amount of extra wiring, including a brake controller, 12v supply and reverse. And I will suggest running the marker lights and possibly the turn signals on a relay with a new larger wire carrying the load, I’ve run into problems on trailers with too many lights for my stock wires that blow my fuses. This is mainly a problem on larger enclosed trailers. 

Most trailer lights have direct LED replacements available cheaply. It helps address the blown fuse situation, and also partly makes up for how janky trailer wiring usually is.