Trailer Brake Controller Prewiring

[s3lekta]

Hey all,
I'm trying to source a wiring harness for my Tekonsha P2 brake controller and it's proving to be a challenge here in Canada. According to an earlier post in this thread, the Tekonsha 304100 harness works for the 2025 4Runners, although the Tekonsha website still only indicates it's compatible with 2014-2023 model years (https://www.tekonsha.com/product/304100_trailer-brake-control-harness).

A local reputable hitch installer exclusively uses a different 304000 harness for all Toyota and Lexus and has had no issues, but hasn't yet installed on a 2025 4Runner. Tekonsha's site indicates the 304000 is only compatible with 2003-2013 model years (https://www.tekonsha.com/product/304000_trailer-brake-control-harness). The local shop has the 304000 in stock. Visually it looks exactly the same as the 304100.

I have a question in to Tekonsha directly on the compatibility but haven't heard back and it's been over a week. I just asked them again. I'm heading out camping in a couple weeks so anxiety is starting to kick in!

Curious if anyone in this forum has any insights into whether the 304000 harness also works? If I were to purchase and test it out, what's the worst that could happen? My thought is maybe a blown fuse...but I'm not an electrician so really am not sure. A "friend" said it could cause serious damage...so I thought I'd throw it out there to see if there's any intel in the community.

Thanks!

You could try the wireless option. Prodigy model or Curt bluetooth

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[JRunner]

Right...as a last resort. I'd only consider the Prodigy but it's like $600-700 CAD. I already have a P2 so a $35 harness is easier to stomach

 

[rfdj]

So the difference is the ring terminal/ additional ground wire. I did talk to Tekonsha before with the same question and the answer was that the system puts out more power. Next version they added the additional ground for protection

 

[JRunner]

So the difference is the ring terminal/ additional ground wire. I did talk to Tekonsha before with the same question and the answer was that the system puts out more power. Next version they added the additional ground for protection

Thanks for that info. I looked at the pictures on the Tekonsha site again after reading your comment and sure enough the ground wire is visible only with the 304100...hiding in plain sight!

 

[JRunner]

Just to put this to bed: I also spoke with Tekonsha directly today and they were super helpful. The 3041 harness also includes the addition of a diode to only send the signal to the controller. If you use a 3040 harness on a 2014 and newer 4Runner, it'll cause your ABS light to turn on. Tekonsha said it's not advised to use the 3040 on the newer 4Runners.

They couldn't officially verify that the 3041 will work on the 2025 model as they haven't tested it internally yet, but the tech was super confident it will work just fine (and we have a case noted in this thread where it works). The worst that could happen is it's wired differently and it shorts out the brake controller. No risk to the vehicle.

I found an online supplier and have ordered the 3041 harness.

 

[JRunner]

Just installed my Tekonsha P2 Prodigy using my 304100 harness. I was originally gonna mount it higher up, below the Aux buttons (see first pic) but it impeded my knee getting in and out, so mounted it lower. Still easily reachable if a manual adjustment is required and more out of the way.

Pretty straightforward if anyone else is considering a similar setup.

Heading out Sunday on our first camping trip, just finished the miles for the break in period.

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