Toyota Sienna Forum - siennachat.com banner
1 - 7 of 7 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter · #1 ·
What trailer wiring harness kit did you use? How did you mount the plug? I know it's super easy to set up 4-pin wiring but my trailer has brakes and needs 7-pin. I don't want to wire the power directly from the 12V battery on the van because my trailer would run it dead when I'm parked.

I'm looking at this Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires
Item # ETBC7
from eTrailer. I'm following along with this Q&A on eTrailer, and I'm considering using a CURT 58000 Easy-Mount Vehicle Trailer Wiring Connector Mounting Bracket for 2-Inch Receiver mounting bracket for the plug.
 

·
Registered
2014 Sienna LE
Joined
·
305 Posts
If you don’t want it connected with the van off than you can still power it straight from the battery and add a standard automotive relay inline that’s switched off the ignition to turn the power to the trailer on and off. I don’t have a 4th gen, but I’d doubt there’s somewhere that’s ignition switched that you could just pull a 40 amp load from. Adding a relay is usually pretty easy though.
 

·
Registered
2014 Sienna LE
Joined
·
305 Posts
Two more items:

First, I’d recommend getting a vehicle specific trailer light converter, if possible. etrailer had a couple options for my 3rd gen. I haven’t looked for 4th gens for obvious reasons. But if you can get it, I’d do that. The vehicle specific one I got has T-connectors, no need to splice wires, you unplug the taillights, plug into the harness, and plug the harness into the connectors you unplugged. A universal one you’ll have to splice wires somehow, and I’m not a fan of the cheap splicers they usually include. I didn’t see a vehicle specific 7 pin kit, but the vehicle specific 4 pin kit had a 7 pin conversion kit available. This will still require splicing in reverse lights and brake controller. Still much less fiddling with wires though. One option (only option currently for 4th gen Siennas on etrailer): https://www.etrailer.com/Trailer-Wiring/Toyota/Sienna/2022/TK69FR.html?vehicleid=20226003149

And their recommended solution, like my suggestion:
Font Line Material property Parallel Screenshot


Second, while I can’t help you locate an ignition switched wire, I can certainly help you with hooking up a relay, if that’s not something you’re familiar with doing.

Oh, third item I guess. Just checking that you’re aware that in addition to that, you also need to get a brake controller too, right? This will also need power, a connection to the brake lights to know when to actuate, and then be wired to the brake line on the 7 pin connector. I recommend getting an intertial based (proportional) brake controller, not timer based. They will work better. Not as great as a factory integrated brake controller…so much better with my 2020 Silverado and factory brake controller vs the inertial controller on my 2013 Pilot. At least the Pilot had a built-in wiring harness for the brake controller up front, so you didn’t need to run wires from the front to rear.

Hmm, this is interesting. A proportional controller that feeds off OBD data for more reliable, even braking. This could certainly be a lot smoother than one that just has an accelerometer, depending one what data they are able to get out of the OBD data stream. (Factory controllers on trucks and the like use brake pedal position smoothly and accurately apply the trailer brakes for a braking experience that’s like you’re not towing anything at all): https://www.etrailer.com/Brake-Controller/Toyota/Sienna/2021/335DL-100.html?vehicleid=202114766

As much as I sometimes didn’t like it, the setup certainly makes me appreciate the simplicity of hydraulic surge brakes like my boat trailer had, and Uhaul trailers use…
 

·
Registered
Joined
·
166 Posts
The top bank on the rear fuse block is switched to the ignition - super easy to run a wire from there to the battery and then down to the 7-Pin. Here is a pic of the fuse block near the right rear seat belt - just pop the panel off, add an "add a fuse" and you have way to trigger your relay with ignition power.

Edit: My above comment/suggestion is in response to post #2. Meaning: you can tap that fuse block for the ignition relay. The power itself should go directly to the battery because, as jseyfert3 said, you probably can't run a high load directly off of that fuse block.
 

Attachments

·
Registered
Joined
·
12 Posts
Discussion Starter · #5 ·
Thanks everyone for your help. I bought a used Curt Echo wireless brake controller so I don't have to permanently mount anything to the van for now. I'm taking the van to a shop to having the 7-pin connector installed; I'll try to convince them to add the relay, if not thanks to your help it looks like something I can easily do.
 
1 - 7 of 7 Posts
Top