I fixed my “Trunk won’t close” issue.

Good find.

Wasn’t the harness part of a recall for the earlier M3s?

Came here to say this 😂

It was. The recall was for previous years. I think they thought they fixed the issue in the newer Model 3s

The previous wire harness issue was using solid core wire instead of stranded wire. If the wire is going to flex often, stranded is better as solid core will eventually fatigue and break. Edit: With citation https://www.tesla.com/support/model-3-trunk-lid-harness-retrofit > On certain Model 3 vehicles, the trunk lid harness is equipped with a solid core coaxial cable that provides the rearview camera feed on the center display. Over time, repeated opening and closing of the trunk lid may cause excessive wear to the coaxial cable. If the wear causes the core of the coaxial cable to separate, the rearview camera feed will no longer be available. The estimated percentage of vehicles with this condition is less than 1%.

Nice of you to show us around. Around your lab table and your work-stool. And your ~~intergalactic spaceship~~ Tesla! And where you keep assorted lengths of wire.

Confidently incorrect. The previous harness also used stranded wire but the new harness has a piece to limit the bend radius of the wires when the trunk closes.

Correction confidently incorrect. Tesla specifically stated it was a solid core issue. https://www.tesla.com/support/model-3-trunk-lid-harness-retrofit > On certain Model 3 vehicles, the trunk lid harness is equipped with a solid core coaxial cable that provides the rearview camera feed on the center display. Over time, repeated opening and closing of the trunk lid may cause excessive wear to the coaxial cable. If the wear causes the core of the coaxial cable to separate, the rearview camera feed will no longer be available. The estimated percentage of vehicles with this condition is less than 1%. Edit: I'm an electrical engineer, I would never spec a solid core wire on a flexing harness.

Solid core coax is different than solid core wire.

It is exactly the same when it comes to work fatigue of the wire. I'm an electrical engineer.

Cable is not the same as wire. You should know that The wires OP had issues with were stranded in the original harness and stranded in the replacement harness

I do. And even the ARRL recommends using stranded co-ax if the cable is going to flex. Keep digging that hole.

Then call it a cable bro. Everybody else calls it a cable but you insist it’s a wire.

> The wires OP had issues with were stranded in the original harness and stranded in the replacement harness Correct. Something nicked his harness, probably during manufacturing at Tesla. He was saying "I thought they fixed that" and I posted the original recall as "no, it was a different problem."

And tell me, what's inside a cable, and what specifically breaks when flexed? Answer: It's the wire in the cable.

Dang, sorry OP

Happened to my 23 Model 3. Trunk would only close a few inches when I hit the button. Took it to the SC and had the harness and latch replaced.

I don’t understand how you had to do all this work on a car that’s only a couple years old… this is upsetting

How much did they charge you? Curious if it was worth doing it myself.

I’m pretty irritated too. Love the car. But, yeah. That’s annoying.

Everything was done under warranty in a few hours

Ive had my 2025 MP3 for 3 months now… Lets just say its been interesting…😅

Lucky you! Mine was unfortunately out of warranty.

Only for the coax, not the regular cables.

Coaxial if for cameras not power trunk.

Same harness. Different issue than OP's.

https://preview.redd.it/6xuqzipko9bg1.jpeg?width=2160&format=pjpg&auto=webp&s=f6b5c192e59544b73383ae05ee13bb010c834e6c Im literally working on the same thing now (waiting for new cord to arrive)

They replaced my harness due to the crimped wire causing the camera to fail. The new harness crimps in exactly the same way at the bend ETA: I saw another post below that the new wire uses braided core coax, so it shouldn't have as much of an issue bending

The hardest part was getting the panels inside the car put back together. I hope it goes easy for you.

Actually it wasn’t too hard (yeah, I disassembled just to investigate, then assembled back since i didn’t have new cord), but i broke some trunk clippers on the way. Maybe because i have 2019 M3 the panels situation was easier for me