2020 Model 3 trailer electrical

[grmdl3]

I installed an EcoHitch on my M3, and found what certainly LOOKS like a trailer pigtail under the bumper cover, just sitting there capped off.

I called Torklift, but the guy I spoke to there didn't seem too clear on it. He tried to sell me an aftermarket adapter, "to keep me from tapping into the vehicle's 12V system." I pointed out that you'd have to do that anyway, it was just a question of whether you had to use relays to attach directly to the battery or were the existing wires designed to handle the load of additional lamps on the trailer. "Good point" was his comment.

Does anyone know if I need anything like this, or if I can just attach the existing pigtail to the trailer directly?

 

[GreenMtnM3]

Tesla makes a trailer light controller that plugs into the box behind the bumper cover on Model 3's produced after the middle of 2019. My understanding is that Tesla will not sell it to you directly in the USA, since the Model 3 is not certified to tow in the US. I recently saw a link to one offered on EBay for $300 on anther post.

Now that the Y is available with a tow package, its possible that it uses the same trailer light converter and you may be able to purchase it at a service center parts desk. Its worth a try. If I recall correctly, the converter was pretty reasonable in Europe (maybe 50 Euro).

I do not believe that you can use the Tesla wiring harness connector to drive a non-Tesla wiring harness. The wires are not straight DC voltages, but there is a power, ground, and a signal wire to 'talk' to the controller box. If you can not source the Tesla controller cost effectively, there are a number of aftermarket wiring harnesses available. I used the Teknosha no-splice harness that has little current sensing loops that go around the tail light wires. It was relatively easy to install and has worked well.

 

[grmdl3]

@GreenMtnM3 I appreciate it. I'd love to at least see what Tesla offers.

Is it this kind of gizmo? The pigtail that's under the bumper looks really like the typical flat, 4-wire connector, not the multipin that's on that EBay ad.