Tacoma Towing OEM

Hello Tacoma World,

First-ever post here so, 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 a 2017 SR, 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

$28 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


There may be a few things I am forgetting to mention but just trying to get my first thread started.

 

Welcome to the forum congratulations on a very organized first post.

The factory towing package is quite comprehensive. The problem you are going to have here is the 2.7 engine, at 159 HP there just isn't a great deal to work with, I believe you are limited to 3500 pounds.

Most U-haul trailers have self contained surge brakes, the double axle jobs probably are beyond the 2.7's capacity to tow comfortably, remember it isn't just the weight but also the frontal profile of the trailer, you are pushing sheets of plywood down the road, fighting the wind.

For such a long distance move I would sell all the furniture, household goods, etc and just move an envelope of cash. With CL, FB, thrift stores, and discounters like Ollie's it is really easy to furnish a place anymore for not too much cash.

 

Welcome to TW!

 

Thanks for the advice RustyGreen, which is definitely a possibility. But, we are planning to sleep in the bed of the truck and have, not a lot but some things, in the trailer to assist in moving 3000 miles to an unfurnished studio. I put a high-top truck cap on the bed so I figured that could help with the trailer's draft a bit. Again, I do hope to someday have a small camper to tow around and I feel the brakes set up will be nice to have. I am a firm believer that as long as I am towing within the weight limits brakes will take a lot of strain off of the vehicle. So I am confident that the little 2.7l in 1st through 4th gear will make the journey. Not to mention that I have spent almost 5 days straight researching how to do this so now I am committed. Plus, someday I might just find a used v6 and drop it in there or maybe even one of those diesel engines I have read about. Granted the transmission may need to be swapped as well, but maybe not, I know nothing.

 

Maybe. You'll need a test light or meter to verify.
You could return/sell the

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

Curt 56349 module...

 

Your SR is also missing the small auxiliary relay box that house the relay to the (TOWING) Battery Charger. And the terminal and wires from the Battery Charger fuse and the Towing Brake fuse and wiring.

 

Ultrasonic sensor wires, not towing circuit. You should get some contact cleaner and the cover so the terminals don't corrode.
https://www.corsa-technic.com/item.php?item_id=1080 Connector (cover)
https://www.corsa-technic.com/item.php?item_id=1055 Cavity plugs

 

Did you happen to see this video?



Also, for the controller, I had excellent results with Redarc

 

This is what I thought exactly, but my confusion is now if I can plug in a controller, where do the wires terminate?

 

I did, but when you installed your Redarc did you have to run the main wires yourself from the redarc pigtail?

 

I am trying to figure out where this would be located in the engine bay. Would this possibly be called "Engine Room J/B"? Or is the fuse box something that needs to be added along with the relays?

 

So this one is for a bumper with backup sensors? Thanks for the links.

 

I had the specific tacoma harness, but that may not be plug n play for you if your truck didn't come with the tow package.

 

Actually that is where an OEM harness plugs in, but good luck getting it from the dealer. Goes from there, under the drivers seat to the rear bumper. I have no clue the part number. From that you only get the 4 pin towing.

 

Your SR doesn't have it. It would right next to the main engine fuse /relay box.

 

Correct.

 

Good idea. Back in '89 I sold everything I owned and bought a one-way ticket from Atlanta to San Francisco, arrived with 1 suitcase and a guitar and a pocket full of cash. Have since lived in 7 other states and that's the best way to go in my opinion. Small apartment should be easy to furnish on the cheap... wish I was young enough to do that again.... let the adventure begin.

 

I am pretty sure I did find this harness in my massive search but may have overlooked it because I ended up with 100 different tabs opened and lost it. But I could keep looking and see if I can locate it. A part number would be amazing because I would still like to get the 4pinflat hooked up in the OEM set-up and then hook up the rest of the 7pin off of it.