2008 Toyota Sienna 7-way trailer harness installation

This video by UHaul showed that off-the-shelf trailer harnesses are sold that have connectors that plug right into a Sienna's existing wiring harness. This would be tons better than doing wire splicing myself:

https://m.youtube.com/watch?v=hvLO-HiYEFE

However, a lot of searching revealed that these harnesses are always to 4-wire harnesses ("flat 4"). I've come to the conclusion that this is because there's no easy way to standardize picking up the power wire for the 7-way connector from the battery, the reverse lights are a huge challenge because they're on the hatch but most trailers you'd hook to a Sienna wouldn't have reverse lights anyhow, and the brake controller is something someone would nearly always have to customize. Consequently, most people posting to forums seem to get the 4-wire harness then get a 4-to-7 wire adapter. Here is the best 4-to-7 system that I've found so far. It has the 3 extra wires stubbed out to butt connectors. It has a nice mounting bracket included. And it's sold in a kit together with a nice 4 wire harness so you know they'll mate together. The instruction sheets are weak but they're available to preview online.

https://www.trailerjacks.com/04-10-Toyota-Sienna-7-Way-RV-Trailer-Wiring-Plug-Prong-Pin-Brake-Control-Ready?language=en¤cy=USD&gclid=CjwKCAjw_o-HBhAsEiwANqYhp0Z0Ly6E_2Hr6V48Nw3tpYa0hWnhopVr6NGZGdlcDHb2Tck6CgJcnhoC8J8QAvD_BwE

Next here are some links to forum posts of people trying to solve this same problem, some of which contain people giving out quite useful info such as specific part numbers for the 12V relay or a brake controller from Curt:

Near the bottom this has a post with some good part numbers: https://www.siennachat.com/threads/7-pin-wiring-ques.1897/

Here's the forum thread answered by madman "Brian" where he cut and spliced two controllers together or something and otherwise did his own wiring. The thread degenerates into a discussion of stranded wire current carrying capacity, so I really should try to read every word in this one even if I was looking for a less labor intensive solution: https://www.siennachat.com/threads/7-pin-wiring-harness-for-2006-sienna.1030/

This thread starts off on fire with a guy giving his entire parts list for his 7-wire install (2012 Sienna though). This thread may have all of the info I need: https://www.etrailer.com/question-83028.html

So, which 4-pole adapter harness is the best? There are a lot of brands out there, including Curt, T-One, and Hopkins.

Here is the Curt harness. Their ad copy makes it sound quite inspired: https://www.etrailer.com/Custom-Fit-Vehicle-Wiring/Toyota/Sienna/2008/C55580.html?VehicleID=20081176415

2008 Toyota Sienna Tow Hitch

The class 3 hitch that John gave me mounts to a vehicle's frame through three holes on each side. The Sienna has three holes in the frame on each side. However it appears as though nearly every other dimension of the hitch will be mismatched, as hitches are not standardized and will be different for every vehicle. It is fairly easy to find vehicle specific hitches however, and they are relatively cheap ($150-$200). The major manufacturers presently for hitches which fit my Sienna are Curt and Draw-Tite. This link is the money hit for chosing between them (oddly the Draw-tite wins on tounge weight and other specs by a lot):

https://www.etrailer.com/question-35975.html

It turns out that YouTube has tons of videos about how to install hitches on Siennas. What I learned is that if I had the plastic underbody cover the job would be twice as long, but since I don't have that then the weld nuts on my frame are essentially destroyed by corrosion and I'm going to have to spend a lot of time chasing their threads. Crazily the UHaul installation videos beat every other one out there hands down.

Here is one of many videos showing how agonizing doing the installation is with the plastic underside cover: https://m.youtube.com/watch?v=GTk8iqXha7Q

Here is the Uhaul vide for installing the Curt hitch: https://m.youtube.com/watch?v=cDU9Wo_MDGY&t=20s

Here is the UHaul installation of the Traw-Tite. The tool list shows the bushing pusher pliers that I will totally want to pop the tailpipe hanger off on the passenger's side: https://m.youtube.com/watch?v=Guz3s1FW7hA&t=18s

Sienna DVD Player Remote and Headphones

Here are some places online to get the remote and headphones for the Sienna DVD player, if the one we buy doesn't have them:

This place seems to have them all, but doesn't specifically have one for the 2007-2010?:

http://www.audiovideo2go.com/toyota-sienna-2005-2006-dvd-remote-control/

Here are the headphones:

http://www.audiovideo2go.com/Toyota-sienna-headphones/

Toyota Sienna AWD Run-Flat Tires

So, it turns out that Toyota makes an All Wheel Drive version of the Sienna. The AWD version does not have a place for the spare tire due to the extra axles, so they sold this version with "Run-Flat" tires, which are supposed to be good for up to 100 miles when flat. Contrary to my expectations, these are not the foam-core tires, but just regular tires with thicker sidewalls, and they apparently barely work for the purpose intended. It doesn't seem as though they require special rims, and apparently regular radial tires will fit on the same rims as the run-flats. On the Penshare Sienna, they'd put plain Yokohamas on the back, but the front ones may still have been the run-flats; they were Bridgestone, and didn't say "RFT" on them as far as I could tell, but I didn't think to jot down the tire number so I could look it up.

Links:

http://www.siennachat.com/forum/89-2011-january-2010-3rd-generation-toyota-sienna/7897-new-tires-replacing-run-flats-nearly-new-2011-limited.html


http://townhall-talk.edmunds.com/direct/view/.f0e6c84

http://www.cargurus.com/Cars/Discussion-t29612_ds437434

http://news.consumerreports.org/cars/2011/06/more-run-flat-tire-wear-issues-on-2011-toyota-sienna-xle-awd.html

The run-flats for later Siennas are 18", earlier (like the 2007) are 17".

I looked up the tire in one of the photos of one of the Siennas posted online, it was Bridgestone B380 and found that yes these are run-flats.