Toyota only does a 4-pin on the Highlander.

You probably need this instead:

2021 Toyota Highlander Custom Fit Vehicle Wiring - Tekonsha (etrailer.com)

 

Strangely it says it replaces the factory 7 pin which is not supposed to exist.
I didn’t have a factory anything, couldn’t find a 2021 with a factory installed connector.
Buyer beware, the dealer installed a 4 pin without telling me.

 

Toyota OEM wiring only comes with 4 pins

 

Was a long time frustration
4 Runners came with 7 pin
Highlanders came with 4 pin
Similar tow ratings

 

I did install a wired connector in the front and replaced the 4-pin with a 7-pin. In fact, I connect the 7 pin into the existing 4-pin and add the +12V, brake and reverse signal with extra wires. You can search for previous post from me to find some picture (and other people contributions).

Best Regards,
jf

 

How did you manage to get the 12 V needed for the brake controller ? I'm trying to do the same setup on mine but wondering how to get the 12V from the battery to the inside of the vehicle. Is there a place to pass the wiring through the firewall from the engine location to the inside of the vehicle ? Thanks !

 

There is a grommet under the carpet on the driver's side.

 

Hi @GPoirier,
I have the hybrid version, so there is a 12V battery in the back of the vehicle. Sorry I don't know the solution for the Highlander.

However I had the Toyota Venza before that. Here is a picture of the firewall grommet on the Venza:

You can see a nipple on the right and the red wire going through the left nipple. If Toyota re-use the same grommet on the Highlander, you should be able to find a similar cable assembly going through the firewall. The one on the picture above was the passenger side one but there was one on the driver side as well.

Good luck and post picture of what you see!
jf

 

Thanks a lot JF, I'm planning to get that done this week-end. I will post some pictures of my findings & solution !

 

Where is a good place to tie into a brake signal to activate the trailer brake controller. Can this be done at the facts trailer light converter box.

 

I did it close to the brake pedal. It was VERY squeezed and difficult, so I would not recommend it. Here is the schematics:

The wire at the option connector would be pin 9 lavender-beige. Note that all lavender wires are ALUMINIUM wires. AFAIK, it is complex and not reccommended to connect to those wire because of the chemistry. So you'd have to follow that wire going to the brake pedal and find the red wire and tap there. You'll need to get the brake controller close to the driver and put the blue wire of the brake controller (the signal driving the actual brake in the trailer) along the same path, so M92 or A73 connector should not be difficult to find. Well, here is the general idea:

Here is M92, really close to converter box:

You may want to check my post regarding the reverse light connection going to M91 connector not far from M92 connector:

DIY reverse light connection on tow 7-pin connection

Hi, I discovered last year that my travel trailer connects the back-up light on the auxiliary contact of the Bergman 7-pin connector. So this weekend I made the connection. Here is the relevant part of the schematics: The goal is to find that M91 connector. That's the main useful information...

www.toyotanation.com

Good luck.
jf

 

If you install an "Autowbrake" brake controller, you don't need to hook up that wire. The unit knows the brakes are applied when both turn signals are energized. Unit mounts in trailer, not the tow vehicle. No need to rewire eveytime you get a new tow vehicle. Has an inertia system as well for proportional braking. Spendy but it works well. E Trailer and Amazon sell them.

 

Where would/did you source the +12v from, on a hybrid for example?

 

10 gauge wire (fused) right from the battery which is under the passenger side, under the floor, way in the back.

 

And this setup would not provide charging power to an on-board camper battery, correct?

Just trying to sort all this out, I'm looking to buy some sort of small camper-trailer for a trip this summer.

 

"Would not provide" ?
No, it does provide power to the on board camper battery, if hooked up to a 7-pin socket.

 

The Autowbrake controller mounts in/on the trailer, hooks up to trailer wiring. Trailer and trailer battery should be getting 12volt power from the tow vehicle via the 7-pin connector. The unit does NOT need to be hooked up to the brake pedal. There are videos on their website. I've had 3 tow vehicles hooked to the same trailer, and never had any issues with it. Have not had to rewire the controller each time.

 

Ah - so no matter what it needs the 7pin from the tow vehicle. I had incorrectly assumed this was an alternative for adding a 7pin in place of the factory 4pin.

 

My two cents. Pay for the Toyota 4 pin harness. This keeps factory wiring. Then use Curtis blue tooth. Then connect 7 point to to 4 point connector with mate connector. Don't splice. This provides factory harness. Run 12v from battery with fuse. If done wrong Hylander have literally burnt up. You overload ECU all bets are off. May start on fire just sitting in your garage. Truly I've seen it. Recommend pulling 12v fuse and unplug 7 pt from 4 pt when not in use. Basically we're asking the car to do what it was not meant to do.

 

I am running into the exact same problem. Bought a 2023 Highlander w/o the factory tow package. Went to a dealer to install the hitch and 7-pin and was told they won't do it because they have had problems with them frying the ECU. Now what do I do? Even if I find an RV place that will do it don't I risk the same problem of frying the ECU?

My two cents. Pay for the Toyota 4 pin harness. This keeps factory wiring. Then use Curtis blue tooth. Then connect 7 point to to 4 point connector with mate connector. Don't splice. This provides factory harness. Run 12v from battery with fuse. If done wrong Hylander have literally burnt up. You overload ECU all bets are off. May start on fire just sitting in your garage. Truly I've seen it. Recommend pulling 12v fuse and unplug 7 pt from 4 pt when not in use. Basically we're asking the car to do what it was not meant to do.

That's helpful. I was looking at the bluetooth but don't understand the technology well enough to know if that solved my problem. You're saying I can connect the Curt plug using a 7-pin to -4pin adapter , then add a 12v wire from the battery to power the bluetooth brake? Will this avoid the fire risk ytoure talking about?

 

You need this:

https://www.etrailer.com/Accessories-and-Parts/etrailer/ETBC7.html

You need to run the 12V supply directly from the battery (+) terminal. Not difficult but tedious weekend project. You need to be careful with the cable routing to avoid chaffing points, exhaust, moving suspension parts, etc. Make sure the cables are well protected from debris.
Once you have the 7-pin connector installed you can use one of these two brake controllers:

https://www.etrailer.com/Trailer-Brake-Controller/CURT/C51180.html

https://www.etrailer.com/Trailer-Brake-Controller/Autowbrake/3430001.html

The Curt Echo is the most convenient and it works. I have one. I use a dedicated old cellphone to control it (without SIM card), so that I can use my regular phone for navigations, etc. That way I avoid the risk of phone freezing due too many apps running at the same time.

 

I use the Tekonsha Prodigy mounted directly on my camp trailer. I only have the brake controller visible when I am actively towing the trailer and I can also use both of our vehicles to tow the camping trailer.

Amazon.com: Tekonsha 90250 Prodigy RF Electronic Brake Control : Patio, Lawn & Garden

Buy Tekonsha 90250 Prodigy RF Electronic Brake Control: Spare & Replacement Parts - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

 

https://www.etrailer.com/Trailer-Brake-Controller/Autowbrake/3430001.html

SO this does REQUIRE a 7 pin connector installed on the tow vehicle after all. There really should be an onboard trailer device that can be tied into the brake lights, accepting the input for a 4 flat and operate the brakes that way. Why would thsi not work?

 

That's not a bad, actually. Weight hurts, but trailers with a lot of windage can really kill mileage. Keeping the speed down helps quite a bit. Low profile boats or pop-ups do somewhat better.

 

HA my RAM 3500 dually gets 16-17 mpg on hwy and 9-10 mpg towing my 12000 lb RV. If I get 14-15 mpg with the 2022 AWD V6 Highlander, I'd be good with that. Esp since Diesel is 4-4.25 /gal compared to 3-3.25/gal for regular gas