"Factory" 7pin Trailer Harness Installation

Here is my version of a "factory" 7pin trailer harness for any 2nd gen (2005+) that didn't come with a 7pin trailer harness. Note: Toyota does not sell a true factory 7pin harness afaik.
Notice: check all wiring diagrams for your truck before cutting/splicing/running wires to make sure your wiring is the same as this. Though this should work on all non-7pin harness 2nd gens.
**If you look under you're truck and you have these 2 connectors (BE1 connector) between the drivers side frame rail and spare tire then you don't need this how-to.


Parts List:
- 1x Sumitomo TS / SL Female Terminal 0.5 - 1.25 mm2 ( 20 - 16 AWG ) *I have a couple for sale
- Crimp Tool for Weather Pack and Metri-Pack
- Factory 4pin harness
{2005-2010:

$150 08921-04960 Towing Wire Harness

08921-04960}
{2012-XXXX: PT725-35120}
-

$28 Hopkins 48470 Endurance Multi-Tow Vehicle Side Connector

Hopkins 48470
- Waterproof 3pin connector set (Metri-pack 630)
- ~25ft Yellow wire (14ga)
- ~8ft Blue wire (14ga)
- Scotch lock or custom taillight coupler *explanation below
- Zip ties
- Brake Controller (Tekonsha P3)

Installation:
1. Feed your Yellow wire through the factory 4pin harness loom. This serves to protect the wire. **optional, it's kind of a pain but it looks better.


2. Install the factory 4 pin harness. We will use the factory 4pin harness that Toyota sells, because why not use what they make available!
4pin installation instructions
2005-2010: 08921-04960.pdf
2012-XXXX: PT725-35120inst.pdf



2.5. In Progress (credit @caribe makaira). Even if you have the 5pin connector (T 7) for the brake controller, you still need power for it. The 30amp TOWING BRK fuse slot doesn't have both connectors in it so you can't just pop a fuse in.

3. Crimp the Sumitumo terminal to the 'cab' end of the Yellow wire.

4. Insert Yellow wire with terminal into Pin-8 of the ID2 connector inside the drivers kick panel. On our trucks Toyota did not put in the wire from the brake controller to the rear of the truck.



5. Route the Yellow wire along with the 4pin harness loom if you did not run it inside of it. Use zip ties as you see fit.

6. Remove the Drivers side taillight and use the Scotch lock to tap into the reverse light (R-W) wire. Alternatively you can make a custom line splice out of an old/broke aftermarket towing harness







7. Route the Blue wire down to meet the 4pin harness. Use zip ties as you see fit

8. **optional, route a 10-12ga 12v+ wire through a relay and fuse/breaker from the battery to the rear along the 4pin harness. Use zip ties as you see fit.

9. Cut your 3 extra wires (Blue Reverse, Yellow Brake Controller, and Power) with a little slack even with the plug at the end of the long 4pin harness loom. Now crimp these three wires in the Waterproof 3 pin connector.


10. Cut the 4pin harness (smaller section) about 1/4 of the back from the Flat trailer plug and splice the square 4pin plug and the 3pin plug to the 7pin trailer plug. **just pretend for now that the 3pin plug is there, and the yellow wire is tucked inside the loom.**



11. Mount your 7pin trailer plug as you see fit.

12. Install your brake controller per its instructions. I am using the Tekonsha P3, simple plug and play. Make sure you get/have the Toyota pigtail to plug the brake controller in.

 

This is where I moved mine too. Super easy to do with a hole saw on the factory bumper. This way it doesn't hang down below the truck.

 

Thanks for the leg work! I am outfitting a 2015 4cyl Pre Runner for towing.

 

I'm glad it could help someone

 

Quick question, your using the factory trailer brake controller plug located next to the fuse box for trailer brake controller power, ground and brake signal? I see how you tapped into the ID2 plug at the missing brake controller wire and ran the yellow back to the 7 way.


I plan on using my curt plug in controller at the back of the truck with a curt 4way to seven way converter and add the brake controller wire. I will be missing the reverse and trailer 12v+ but not a big deal for my 16ft flat bed.


Just think I just got rid of a 2013 f150 lariat crew cab 4x4 eco boost......I miss that truck no rigging wires....

My 2008 4Runner has the factory hitch and 7way simply plug and play.

 

Yes the brake controller will plug into the factory harness, you will need to make sure you get a controller with the Toyota pigtail or buy it seperate.

 

Thanks for the clarification.

 

Here's the controller I got, it comes with the harness

$200 TEKONSHA P3 BRAKE CONTROL + WIRING HARNESS FOR TOYOTA 4RUNNER, LANDCRUISER, SEQUOIA, TUNDRA TACOMA & LEXUS LX570 GX460 LX470 GX470. CONTROLLER + PLUG/PLAY WIRE KIT.

http://www.amazon.com/dp/B007O5GXOG/ref=cm_sw_su_dp

 

That's a descent controller i installed one on my 2008 F150 worked well with my 19ft travel trailer

 

I am going with a Reese POD and putting it in the drop down change holder where the fuses are so I can hide it. This truck has a very small interior

 

Just for my clarification, the metri pac 3 way connector is used in step 9 correct?

Thanks! And thanks for the write up!

 

Correct, I just didn't have it in time for the write up. This reminds me I need to reinstall it after the frame swap.

 

For Battery Charging..right?

Props for the install...

 

Correct!

 

Any recommendations as to where to get the metri-pack 630 3 pin connector and theSumitomo TS / SL Female Terminal 0.5 - 1.25 mm2 ( 20 - 16 AWG )?

What AWG should the metripack be for?

Sorry for all the questions! I'm finding them online, but would prefer a recommendation if someone had a good, fast-shipping, source.

 

How did you get juice to the trailer break control since your '06 didn't have the tow from factory?

 

I got the metripack from eBay and the sumitomo from Ballenger autosport. Metripack awg should be enough to handle 12v power for charging trailer batteries (10 or 12awg) , or smaller if you don't want that (14 - 16awg).

My truck had the plug in for the brake controller tucked away in the side kick panel. Just have to find it and plug in the brake controller.

 

So your engine fuse block had the 30 amp towing brake fuse slot ready...nice

 

Wonder if mine does...

 

Mine didn't/doesn't...