So 4 PiN tOw ??? Where Do you Go

Hello all Thanks for Stopping by.

Anyone else have an 04 tundra sr5 3.4l with a mounted 4 pin trailer control thingy (the Technical term) it's wired in quite like it's been there from the start but no mention of it. And if someone has my clue, where does it end up ? To hook up a tow control.

Thanks

 

If you are talking about a brake controller the wiring would be located in the driver kick panel towards the left side. It’s a white connector if I remember correctly. You can also change out the 4-pin connector to a 7 pin if you need.

 

Ehhh if his truck doesn’t have the tow package the connector is still under the dash but the engine bay harness and the frame harness will not have the wires for it to work. I had to replace my fuse lock harness and frame harness to have a working factory 7 pin

 

A 4-pole connector doesn't have a provision for trailer brakes. The 4 contacts are left signal, right signal, tail lights, and ground. In order to have a controller for trailer brakes you need a 7 pole connector, so you need a 4 pole to 7 pole adapter. Scroll down to the bottom photo and it shows how it's wired. You plug the 4 pole plug into your existing 4 pole, then tie it up out of the way. That takes care of your signal lights. Then you have three more functions to connect:
1) constant 12V (ie: for charging a battery on a camper)
2) trailer brakes
3) aux/reverse lockout

I didn't bother with #3 because I don't have a need for it. So I ran a length of this wire to the front of the truck -- it's made specifically for this purpose. It has two wires: one to carry 12v power, the other to carry the output of your brake controller. You need to protect each circuit (the constant 12v, and the trailer brakes) with a 20A circuit breaker -- so you'll need two.

That site has great how-to videos to walk you through the process if you're unsure of anything.

 

Something like this is also an option.

 

That's the wrong "gender". It allows you to connect a truck with a 7 pole wiring to a trailer with 4 pole wiring. Notice the 4 pole connector is the same as the 4 pole in the OP's post.

 

I didn't notice, thanks. How about this one?

$17 MICTUNING 4-Way Flat to 7-Way Round Blade Trailer Adapter Wiring Plug Connector with Mounting Bracket

https://www.amazon.com/MICTUNING-Trailer-Adapter-Connector-Mounting/dp/B07WYXPWP5

 

So is the plain Jane 4pin just a standard OEM attachment? Seems kinda a waste to include one end mounted and usable, but leave other buried. Like here's a Partial Package lolol.

 

That would do it! I'm surprised they actually sell that though. If a trailer has brakes, it's generally at such a weight that brakes are required by law. To pull a trailer of that size without brakes would first of all be illegal, but more importantly, unsafe.

Having said that, I've done it before while being very cautious.

 

The 4 pin you have there will work as is. Brake, tail, turn signals. That’s it. The 7 pin was part of the tow package. The only part of my truck that was wired for tow package was the dash harness. Everything I added

 

So where does the 6 pin fit into all this? All the trailers and vans at our shop have those, except out 1 ton truck has the 7 pin, which we adapt to 6 pin.

 

I've seen the 6 pole, but never owned one or used one. Going by this description, the only difference is that it doesn't have the aux/reverse lockout.

 

6 is kind of just an old relic. I mean it’s still around. But almost anything modern is a 7 pin. I believe all a 7 pin does is add a reverse light

 

The reverse/lockout is to disable brakes while in reverse. Reason being that when you accelerate in reverse, your brake controller (or surge controller on some boat trailers) senses the reverse acceleration as deceleration, so applies the brakes. Not a big deal if you're backing slowly on flat ground, but gets particularly problematic when backing uphill.