Towing OEM 4/7 pin

hello everyone. I have inherited a 2017 SR and I am about to move out to Sacramento CA from WV and hoping this little truck (w/ aux Tcooler) can get the two of us, our dog, and as much stuff as we can fit into a 400sqft apartment. I know my truck cannot handle a huge load but I would like to have the 4/7 OEM set up so that 1) I can take a small Uhaul possibly one with a single axel without brakes(4pin) or one with double axel and brakes(7pin); the latter to help with wear and tear on the truck and 2) someday in the future my wife and I can hook up to a small camper and have it all ready to go.

After loads of digging through TW I have found SO MUCH information, but still not able to find what I am looking for. I have looked at the fuse panel diagrams and wiring diagrams and found that this truck seems to have the basic wiring in the harness for at least a 4pin and or possibly 7pin plug-and-play components. I would venture to guess if I knew the OEM part number from a 2017 LIMITED w/tow it would all plug in. Most of what I find in TW is the tried and true method of running 12v from the battery to the 7pin connector, a brake signal wire to the controller then the 7pin, and the reverse light (this one is hard to figure where to tie in). I have also read and am slightly concerned about using the Hopkins adapter harness with regards to potential power back surging through the tail lights and creating certain problems. I would hate to be blowing fuses and/or relays after thinking I did a good job.

I have found 2 multi-pin connectors:

1. [4 pin black square] behind the driver's kick panel with (~10awg)solid green,(~10awg) white with black stripe(tracer?), (~16awg) blue, (~16awg) purple.

2. [10 pin black rectangle] behind the bumper on driver's side frame rail (~16awg) tan, (~16awg)purple.

It seems strange to me the 10pin connector has only two wires to it, so I am starting to think it has nothing to do with the towing. But the black 4pin square seems like this part is for it to connect to a brake controller adapter like this one from curt,

https://www.rockauto.com/en/moreinfo.php?pk=8206748&cc=3441741&pt=15581&jsn=673

Q: What type of brake controllers are compatible with this adapter?


I have checked all required fuses and relays (both engine bay and drivers side)I am only missing the :
40amp BATT CHG
40amp TOWING BRK NO1

Q: Are these called fuses? They seem like a different type of fuse but not a relay.

Ultimately I would be happy to hook up a 4pin flat trailer connector if that is what the current harness is equipped for and splice in the 7pin round connector as well as run the 12v wire to the battery. I was hopeful the truck was wired at least for the brake lamp and reverse lamp to function and I could run the 12v power separately. Ultimately if there was an OEM system in place to send the brake light and turn signal to a 4pin flat I would be happy because it should be very simple to hook up the 7pin off of that and be able to use the truck fuses and relay systems.

I have read into the towing bible and many threads on this but still coming up short on a few key points specific to the 3rd gen Tacoma insofar as the factory harness is equipped and how to find out what the OEM part numbers would be so one could cross-reference them with possible parts from other Toyota makes and models, both OEM and aftermarket.

It is my opinion Toyota would not make a separate wiring harness for the SR w/o tow and the LIMITED w/ tow considering they are not adding all the components from the LIMITIED to the SR in the first place for saving time and money on the business side of things and allowing them a base model.

I have ordered all parts necessary to install a 4pin/7pin towing setup but would like to make it as plug-and-play as possible. Here is a list of parts I have ordered:

$66 CURT 56349 Vehicle-Side Custom 4-Pin Trailer Wiring Harness, Fits Select Toyota Tacoma

https://www.amazon.com/gp/product/B074HBSQ5B?ie=UTF8

$30 Hopkins Towing Solutions Hopkins 40975 Multi-Tow Plug-In Simple Wiring Kit

https://www.amazon.com/gp/product/B001NYYREC?ie=UTF8

$27 Hopkins Towing Solutions 40985 Universal Multi-Tow Harness Connector

https://www.amazon.com/gp/product/B005Q87T6E?ie=UTF8

$17 Fastronix 30A 12V Type 1 Automatic Reset Circuit Breaker with Cover 2 Pack

https://www.amazon.com/gp/product/B084RGQFQX?ie=UTF8

also

-an AGILITY brake controller only because I have a used one along with some of its spare components and wires. (If I shouldn't use that one I am thinking the AGILITY over the TEKONSHA unless TW has something to say about which one to use)
+a fuse tap (10amp)
-heat shrink tubing
-heat shrink connectors
Q: Should I solder the connections? I just think these will work well but not as well as solder, probably personal preference here.
-Scangauge II


Thanks to all the members (both mentioned and not) for the insight:
splitbolt for the wiring diagrams and
gearcruncher for the info on auxiliary transmission coolers
maverick491 for the towing bible

 

So I am not sure why no one has responded... I can't help with the harnesses etc, but I can tell you that all the uhaul trailers use 4 pin flat connectors, and they have surge brakes, which don't require a brake controller... so you can save a bit of money there.