Tesla Model 3 2020 SR+ rear trunk and license plate lights problem

[blue_phantas]

Hello everyone. It seems that both problems appeared at the same time:

1. When I open the rear trunk, trunk lights turn on for one/two seconds and then turn off. Also strange sound from the hatching mechanism. Same when I try it from the app. It opens the trunk, but then the car thinks the trunk is being closed again. Please note this is manual trunk, not automatic. It seems that the car is getting invalid signal from the hatching mechanism (it thinks that the trunk is closed, although is open). Mechanism, cables looks ok.
2. License plates stoped working: simply no light. Even when I try to turn on lights manually, these plate lights are still off.

I tried to restart tesla system (holding two buttons), but it didn't help. I have disconnected connectors from locking mechanism (also the locking sensor is working properly) as well as from the plate lights. Didn't help.

To me it looks like either signal fault? I am not familiar whether tesla 3 has some fuse box. Any idea? Thank you

 

[blue_phantas]

Hello everyone. It seems that both problems appeared at the same time:

1. When I open the rear trunk, trunk lights turn on for one/two seconds and then turn off. Also strange sound from the hatching mechanism. Same when I try it from the app. It opens the trunk, but then the car thinks the trunk is being closed again. Please note this is manual trunk, not automatic. It seems that the car is getting invalid signal from the hatching mechanism (it thinks that the trunk is closed, although is open). Mechanism, cables looks ok.
2. License plates stoped working: simply no light. Even when I try to turn on lights manually, these plate lights are still off.

I tried to restart tesla system (holding two buttons), but it didn't help. I have disconnected connectors from locking mechanism (also the locking sensor is working properly) as well as from the plate lights. Didn't help.

To me it looks like either signal fault? I am not familiar whether tesla 3 has some fuse box. Any idea? Thank you

Additionally I just learned, that part of the back lights, which are located on the trunk lid, aren't working as well. So it seems overall problem with the trunk lid electronics.

 

[normalnot]

Hi there,

I have EXACTLY the same problem as you, as of 1 week ago. Before that everything was OK.

My notes are:
1) I have an aftermarket trunk closing kit installed a long time ago, and I was originally suspicious it was it's fault
2) recently installed new firmware
3) recently I went to Tesla to replace the rear OUTER tail light (not the one on the trunk gate) under warranty, and maybe they messed something up.

How is your situation? Did you fix it?

 

[Izzy1315]

Hello everyone. It seems that both problems appeared at the same time:

1. When I open the rear trunk, trunk lights turn on for one/two seconds and then turn off. Also strange sound from the hatching mechanism. Same when I try it from the app. It opens the trunk, but then the car thinks the trunk is being closed again. Please note this is manual trunk, not automatic. It seems that the car is getting invalid signal from the hatching mechanism (it thinks that the trunk is closed, although is open). Mechanism, cables looks ok.
2. License plates stoped working: simply no light. Even when I try to turn on lights manually, these plate lights are still off.

I tried to restart tesla system (holding two buttons), but it didn't help. I have disconnected connectors from locking mechanism (also the locking sensor is working properly) as well as from the plate lights. Didn't help.

To me it looks like either signal fault? I am not familiar whether tesla 3 has some fuse box. Any idea? Thank you

I have a similar problem? Did you resolve this?

 

[Dabid]

Same issue. Also have aftermarket lift gate. My camera, latch trigger and reverse light all work fine. Just no license player lights and tail lights on hatch section don’t light up. I know it was working for sure until recently. Did bring in for ‘harness check’ and possibly stopped after latest update (not absolutely sure). Have a mobile service appointment tomorrow. Wonder if they will still fix u see warranty. Lift gate has was installed about 1.5 years and no issues until now.

 

[Perscitus]

Might be the trunk harness failing (see recall thread stickied in the forum).

The harness wiring handles:
- rear view camera
- trunk inner tailight sub-assemblies
- license plate lights
- trunk handle / open actuation

The aftermarket wiring fished through the OE path may or may not be contributing to the OE wiring failing, or Tesla has finally made some breaking changes in their CAN bus messaging when aftermarket auto-trunk is present.

 

[pobguy]

My trunk light also does not work. I tried switching out the led with some spares that I have, but still doesn't work. The license plate lights work, as does the rear view camera and the auto-trunk. Is there a fuse I can check?

 

[Snowball316]

I just have the same issue today. Out of warrenty and set an appointment for mobile tech tomorrow. Estimate is $180. I hope and does sound like a harness issue.

As you can see from the image trunk lights and license plate does not light up.

 

[Snowball316]

Update: service tech was able to replace harness under "recall" and the lights work again.

 

[CuriousM3]

Just noticed the same issue on my car as well, looks like I will need to wait for the harness recall,
When I try to schedule it , it says I’ll be notified when parts are available?

glad I found this post

 

[Perscitus]

Parts are available, see dedicated thread for the recall.

Half of the car is torn apart to replace. Great design strikes again.

 

[Snowball316]

Parts are available, see dedicated thread for the recall.

Half of the car is torn apart to replace. Great design strikes again.

Incorrect I just had mobile service perform recall on side at residential area. The phase "car is torn apart" is not the case. Only trunk panel is removed and the harness is disconnected and reinstalled with the recall replacement.

 

[Perscitus]

Correct. If they only replaced parts of the harness leading to the tailights, then all thats needed is what you described. Lucky.

However, if the entire harness needs to go (as stipulated by the recall) then most of the C pillar trim, door bolster trim, rear shelf cover, followed by all the branches of the harness under the trunk panel cover.

Refer to your online service manual for the detailed step by step breakdown and a speed-run video from a service center.

 

[CuriousM3]

So when you had yours replaced, you had all the branches outside of the just the trunk harness replaced as well from the beginning of the C Pillar to the trunk panel?