Over the past few months I have installed a Toyota OEM hitch, etrailer custom 4-pin wiring kit, 4 to 7-pin conversion kit and a Prodigy P2 brake controller on my 2013 Highlander Base 4WD V6. Here are the etrailer links:
What's nice about the etrailer site is the many installation videos for the parts/kits that they sell. The 4-pin link has video clips for several different years of the Toyota Highlander.
The 4 to 7-pin conversion kit also has two separate Highlander videos and each also includes a different Prodigy brake controller install as well.
Some comments on the 4 to 7-pin kit and the installation of the components:
The kit contains enough wire cable to go from the back of the Highlander all the way underneath the vehicle and up into the engine bay. As the video shows you will have enough wiring left over to run some wire back through the firewall to the brake controller. Stringing the wire along the underside has a few challenges. Be careful going over the rear driver wheel area. Lots of linkage in this area and you need to secure the wire with zip ties so that it does not sag or droop. As you approach the middle of the SUV you will encounter a fairly good size plastic shield that needs to be partially removed to route your wire and tie it securely. The shield uses those plastic pop fittings and a couple of threaded bolts that need to be removed. It looks easy in the video but when you are using jack stands and laying on your back it can be a bit challenging at times. Watch the video to see where to run the wire up into the engine compartment. Your wire should come up between the firewall and the air filter plastic cover.
Make sure you use the correct breakers and mount them as shown. Also pay attention to the ring clamps that you use. Use the small ones for the connections to the breakers and the large ring connectors for the + and - battery connections. I used an electrical metal fish tape from the inside driver side to push through the firewall grommet. On the 2013 that grommet is hidden behind the floor carpet material. Don't push too much tape into the engine compartment as it will get hung up when you go around to find it from the engine bay. Let's just say that you need small hands to find your pull tape as it is hidden behind the brake fluid assembly. Once you have your fish tape secure the wiring and pull it back inside the vehicle. You have to do this a second time in order to get the necessary 3 wires for the brake controller. Again watch the video carefully and you should be okay.
Everything so far was fairly easy and just required a bit of patience and taking one step at a time. Now comes the fun part. On the brake controller you need to connect the "red wire" to the SUV's brake switch. For my 2013 Highlander the video shows that the brake controller red wire needs to be attached to the "blue" wire on the brake switch using a plastic clamping connector. Looks easy in the video! I must have spent an hour looking for that brake switch with half of my 6' 3" body hanging out the drivers door. Turns out you "cannot" see that switch with your head next to the brake pedal because Toyota, at least for 2013 put a big fat, black plastic air duct right in the way!
I had to pull off the plastic housing below the steering wheel (carefully) and let it hang while I looked into the mess of wires and parts. That darn switch is to the left of the steering column and inside the dash about 10-12 inches and just below a sharp metal bracket. Getting the clamp over the blue wire on the switch and the red wire from the controller along with my hands and a pair of pliers was an exercise in self torture. After a whole lot of trying I finally did it but I must have made around 20 attempts. Not sure what year Highlander you have but this is a bear on the 2013.
I followed all of the remaining instructions and attached the Prodigy P2 and plugged in the back connector. I mounted the P2 just to the right of the small fold out pocket door on the lower dash. I put the key in the ignition and turned the vehicle on. The Prodigy LCD display ran through some characters and finally settled down to just two blue dots. That indicates that the Prodigy is working and that "no trailer is attached". According to the instructions the two dots should disappear (blank screen) after 15 minutes of no motion. Sure enough after 15 minutes the display was blank!
Next week I will be testing the system by hooking up to a friends pop-up camper. I'll let you know how that works out after the test.
In the midst of all this I decided to also install a wired Hopkins back-up/trailer towing camera as well. Long story short the wire is all routed along the inside of the vehicle up to the front, across the driver foot well and the cable comes out in that little side pocket on the vertical part of the center console next to your right foot. At least on the 2013 Highlander their is a small pocket that I had to drill a 5/8" hole to get the wire connector head out and into the pocket. The camera is up and working and what's nice about it is that it has a superimposed set of grid lines for routine backup and at the push of a button shows a different grid pattern for backing up to a travel trailer coupling. On top of that it also has an audible system that single beeps, double beeps and really sounds off very rapidly depending on how close you are to an object. You can shut the audio off, control screen contact, color and sharpness!
Enough for now!