Charging wire - Event Date: 27 Nov 2016 - 10 Dec 2016

Originally posted by furpod OK, so far, near as I can tell, you don't actually KNOW what is back there. Correct? Before we go hacking up the wiring harness etc on a brand new computer controlled modern vehicle, lets make sure we NEED to. If Toyota did this, I PROMISE they didn't cut into your wiring harness anywhere. If the Highlander actually came with a factory tow package it WILL have a plug in pigtail for the trailer wiring harness. It probably has one in the driver's area for the brake controller too.. Just so you know, with modern cars and trucks, if you go hacking in extra wiring, lights etc, they often will give an error code, possibly even shut down, when they "see" the drop or increase in voltage on that circuit. Really. Your Toyota has more processing power then the Lunar Landing missions had access to. Just a quick look under the rear, at the back of the Bargman connector and you should be able to follow the wire bundle to see if it goes randomly, or to the factory harness.

Unfortunately, not all cars with factory tow packages come with a dedicated pigtail. My Escape (2016 SE with factory tow package) did ot have a dedicated connector for a brake controller. It came with a 4-pin connector. I needed to use the ETBC7 Universal wiring package from eTrailer. That is why I suggested that the OP refer to eTrailer in order to connect the brake controller. They were a great resource, not just for the equipment, but the expertise. They have videos that are helpful also.

I just checked on eTrailer. The Highlander will require the ETBC7 Universal Installation Kit or the equivalent homemade kit to connect it. Since the Bargman connector was already installed, the wire and breaker with appropriate connections may be the main thing needed. There will be two wires to run from front to back. The one is for charging. The second is connected to the brake connection to power the brakes. I'm not home, so I don't have the instructions available to look at, so I can't be more specific at this point.

I agree with furpod up to a point.  My Toyota Tacoma had a 4 pin trailer connector.  I had it in the shop for something completely unrelated but had just bought the r-pod so I asked the dealer to install a Bargman connector.  No problem (just $).  Well, in the first place they did not provide power to the aux terminal. Second, they just spliced into the wiring for the trailer lights on the 4 pin connector.  So, 12V aux power was not delivered to the pod when hooked up to the tow vehicle and the fridge drained the battery.  I then ran a wire from the battery to the Bargman aux terminal.  However, the Bargman ground was the ground to the 4 pin trailer lights (way too light for running the fridge).  So, in addition to the 10 ga positive wire I ran a 10 ga negative wire to the Bargman.  Furpod is right, you've got to know what you have got.  Get under there and examine the wires that connect to the Bargman.

From everything I can find out, including documentation from Toyota, the Highlander's "towing package" is more like a partial towing package. Here is a quote from http://www.toyotaofdecatur.com/blog/2016-toyota-highlander-towing-capacity/

"The towing package that comes standard includes a heavy-duty radiator with engine oil cooler, 200-watt fan coupling, supplemental transmission oil cooler and 150-amp alternator. All this allows V6 models to tow a trailer up to 5,000 pounds!" The "towing package" is more like a Towing Ready package where the owner or dealer has to add the rest of the parts needed to actually use it for towing such as the hitch receiver and electrical connector.

The eTrailer web site does not list any sort of dedicated wiring harness for the Highlander, but for all the models listed, calls for use of the Universal Installation Kit.

We are home now, so I I looked up and saw that there was a video for installation on a 2014 Highlander. It should also help with installation on the 2016 Highlander. Here is a link for the page:
Universal Installation Kit
Under the Videos tab, scroll down and select to view all the videos. Scroll down on the list and toward the bottom is the video for the 2014 Highlander. This video will help to see what is needed to install a controller. Unless the Toyota manual specifies that there is a connection for the controller, I would trust eTrailer's statement that the kit (or equivalent) is needed. Since the round connector is already present, it is the wiring and breakers that are the main thing needed. If the ground was just spliced in to the vehicle's taillight wiring, then a better ground to the vehicle frame would also need to be run.

I hope you are successful in getting this done. The video should help.

I'll reiterate that you need to use 10 (or 8) gauge wiring for the +12 connection. I've run through the numbers here a few times showing why the 12 gauge wiring usually installed by the manufacturer and places like U-Haul is inadequate.

However, no need to run 10 gauge from the battery to the negative connection. You want to connect it to the body as close as practical to the Bargeman. Since that is a short run you can use a smaller gauge wire - but I still recommend 10 or 8 gauge. You just don't need to run 15 feet of it to the battery.

Thanks everyone for your comments.  I never had any intention of fooling around with those wires myself. I know enough to stay away from something that I have little knowledge of, especially with today's complicated vehicle electrical systems..lol. Much rather leave it someone who deals with it every day.