2015 Tacoma with trailer wiring ripped out, help!

I posted this in the towing section but it was suggested i post it also in lighting, so here goes...

Hi folks, i just purchased a 2015 Tacoma in sweet shape for its age; 4 cyl 5 speed with a mere 100k on it from an estate.sale. It is so fun to drive!!!!! One glitch, that based on what I learn from you experienced folks, I may or may not have to live with. The prior owner used it to haul a tiny travel trailer from "up north" down here to Florida each fall, and then back up again in the spring. (Most of us residents smile & nod gracefully at such people coming down here and leaving their money). Some time before the deceased part taking place and causing the sale (and my eventual good luck), he backed over something (without trailer attached) and completely ripped out the 7 point wiring harness. Me, being the kind of guy who doesnt like to see things broken for long, went from the tag agency straight to the auto parts store and got a new 7 point assembly. I get home, crawl under, and start muttering "WTF" in the two languages I know (similar hand gestures in a third) as I find the wires match no known wiring harness color codes as there was no purple, two whites, and two yellows in addition to the normal rainbow. BUT tucked way up high out of harms way, is also a 4 pin flat female. Sweet, I think and start to unsnarl wiring that would suggest a weedeater mating with a Tasmanian Devil, only to find THAT flat 4 isnt even wired into any of the same wires which kinda sorta connected to the obliterated 7 pin! I unsnarl (is that a word?) more of carefully taped up 7 pin wires (it was actually a really nice job) and at some point the bundle of wires connected to the 7 pin literally fall out. Evidently the prior owner had set it up so that he traveled the entire eastern seabord twice a year with just brake lights through the 7 pin!! I unravel more of what i think is the intended 7 pin wiring and get to what looks like factory wiring. but there is just 3 wires, heavy gauge- black, red and white. Im missing 4 or 5, arent I?
Soooo..(and here is the question) how do i somehow use the 4 pIn flat (which i assume to be wired in correctly on its own wiring harness) and those three much heavier wires (which actually went somehow to the destroyed 7pin) to hook up my new 7 pin plug? Yes i know I cant pull much but sometimes the other (monster) truck is in the shop and i have to move my trailer (electric brakes but no auxilliary power) around town. I dont want to use the 4 pin and no brakes. Anyone ever done this? If so, how? Thanks tons in advance!

 

Welcome to Tacoma World and congrats on the new-to-you truck!

I'm no expert but saw a similar thread just the other day, check out the link below it may help get you started to figuring out the parts you need. Good luck.

https://www.tacomaworld.com/threads/cut-trailer-wiring.816885/

 

Thanks, good suggestion. I checked out the thread you referenced and slobbered over that oem wiring harness til I found out it was A) over 200 bucks, and more importantly when I went to order one anyhow B) wouldnt fit my model unless i cut the ends off and wired it in (back to my original question of what colors,where), negating the possibility of plug and play fun stuff. Sad. There was a color code diagram there that may be of use tho, but I think im going to have to sit down with my multitester and a fistfull of pigtail wires and swear more.......

What part of Wisconsin? I grew up near Beloit.....

 

Welcome to the forum

If your existing 4 pin flat connector works you can purchase a kit that plugs into that directly and only have to sort out the remaining 3 wires for brakes, charge and reverse.


Like this: Hopkins Towing Solutions 47185
https://hopkinstowingsolutions.com/products/vehicle-side/7-blade/47185.html







You can get one of these handy testers for just a little money.



For a bit more you can get one that does the 7 pin connector too.

 

I would highly recommend going to a Toyota dealer and getting the correct (plug and play) harness. No matter how elegantly you try to piece something together and splice it in from a "generic" plug, you're likely to have problems either right away or down the road. I work at a Toyota dealership and when a truck comes in with electrical gremlins, one of the first places we look is the trailer wiring. All too often we find hacked up / damaged wiring there that causes all sorts of problems.

As for flat-4 vs the round-7, getting the factory harness gives you the round-7. Plugging in an adaptor gets you (correctly) down to a flat-4.