Automatic Model 3 trunk open/close

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telero

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#61
After @JWardell and @fast_like_electric showing some concern with the CAN bus connections, I discussed with my wife the concerns and her needs for the this and we decided against connecting to the CAN bus. The main thing wanted was to be able to open the trunk with the foot sensor while the car was asleep. For that the foot sensor (and controller) need the always on power source, so we did end up running the power up to the drivers side connection rather than using the switched power under the rear seat. Hopefully there won't be any 12V nag screens.

Since we didn't connect the CAN bus, the only thing that seems to not work is closing the trunk from the app. Because this version doesn't trick the car into thinking the trunk is always closed, the on-screen trunk button was never an option for closing. Without the CAN bus allowing the app to close the trunk we did run the remote close button to the drivers side footwell with the power.

After watching about 5 different videos that showed the various methods that can be used to do the install, we were pretty confident in what was needed to be done and I would call the install fairly easy. It did take us all day, but we were going at a leisurely pace and took various breaks throughout.
 
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#62
Since we didn't connect the CAN bus, the only thing that seems to not work is closing the trunk from the app. Because this version doesn't trick the car into thinking the trunk is always closed, the on-screen trunk button was never an option for closing. Without the CAN bus allowing the app to close the trunk we did run the remote close button to the drivers side footwell with the power.
The question comes back to what exactly they are using the CAN bus for. I'm assuming that without the bus, they have no way of knowing that the car is 'in gear' or moving. In which case, if you install the foot sensor and you drive over something that looks like a foot wave (say a dead squirel), the trunk could open when you don't want it to. It also seems like the device would not know when the vehicle was locked, so the foot wave with a locked vehicle would open the trunk.

I guess I was thinking that the CAN bus connection would be required if you install the foot sensor - otherwise you run the risk of an unsecured trunk or an unattended trunk open while driving.

Without the foot sensor, seems ok to not to connect the CAN bus - as long as the product works (which you've confirmed).
 

telero

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#63
if you install the foot sensor and you drive over something that looks like a foot wave (say a dead squirel), the trunk could open when you don't want it to. It also seems like the device would not know when the vehicle was locked, so the foot wave with a locked vehicle would open the trunk.

The foot sensor taps the signal line for the built in trunk switch. I believe that anything that stops the trunk switch from opening the car would stop the foot sensor as well. I don't believe the foot sensor actually connects directly to the controller. It has a 12V constant line (taps the 12V to the controller), 12V accessory line (unused), ground, and trunk switch line tap.
 
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#64
The foot sensor taps the signal line for the built in trunk switch. I believe that anything that stops the trunk switch from opening the car would stop the foot sensor as well. I don't believe the foot sensor actually connects directly to the controller. It has a 12V constant line (taps the 12V to the controller), 12V accessory line (unused), ground, and trunk switch line tap.
Ah, makes sense. Yes - if the foot sensor hooks up as just another trigger to the external trunk switch, then yes the logic in the car will prevent openning when locked or moving. It wasn't clear to me how the foot sensor wired up - thanks for the clarification. Should work good then for most applications without needing the CAN connection. Would be great if the vendor would confirm.
 

Skione65

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#65
After @JWardell and @fast_like_electric showing some concern with the CAN bus connections, I discussed with my wife the concerns and her needs for the this and we decided against connecting to the CAN bus. The main thing wanted was to be able to open the trunk with the foot sensor while the car was asleep. For that the foot sensor (and controller) need the always on power source, so we did end up running the power up to the drivers side connection rather than using the switched power under the rear seat. Hopefully there won't be any 12V nag screens.

Since we didn't connect the CAN bus, the only thing that seems to not work is closing the trunk from the app. Because this version doesn't trick the car into thinking the trunk is always closed, the on-screen trunk button was never an option for closing. Without the CAN bus allowing the app to close the trunk we did run the remote close button to the drivers side footwell with the power.

After watching about 5 different videos that showed the various methods that can be used to do the install, we were pretty confident in what was needed to be done and I would call the install fairly easy. It did take us all day, but we were going at a leisurely pace and took various breaks throughout.
@telero,

I was under the understanding that the 12V power under the rear seat was ‘always on’ and not switched. Is that correct? You are saying it is switched? Do you have a source for this?

Ski
 

telero

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#66
I was under the understanding that the 12V power under the rear seat was ‘always on’ and not switched. Is that correct? You are saying it is switched? Do you have a source for this?
Just what I was remembering from the aftermarket sound system thread. Maybe I'm misremembering or misunderstanding though. I thought people were using that location for their amp power since the DC-DC was only on when the car was on (or charging the 12V battery). I know there has to be a connection to the 12V battery at some point, but I thought it was isolated when the DC-DC was off, otherwise you'd be drawing from the 12V battery which could possibly cause some 12V error messages.

@JWardell and/or @Ingineer could probably give a more definitive answer.
 

JWardell

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#67
Yes the 12v screw on the PCS is always on, but the car may detect a draw from it when it doesn't want to and trigger an error demanding replacement of the 12v battery.

But why not just attach to the switched accessory 12v? It is on whenever the car is awake, which is always if you use sentry, and if not just wake the car by launching the app before walking out with your handful of stuff.
 

MrTofuDragon

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#68
I may have to rerun my 12V to either VC left or just use VC Right as that would be close. I'll have to see how hard the panel is to remove with the glove box being there.
Hi barjohn, I don't think anyone actually did it but I did remember having this discussion with you on this thread so I thought I'd come back with an update. Essentially, DO NOT CONNECT ANYTHING TO VCRIGHT to get 12V power. VCRIGHT needs to shut down when car goes to sleep and anything connected will keep car awake and eventually throw 12V Battery Errors.

I learned this the hard way when I installed TeslaOffer's frunk kit last week and used VCRight for power. About 5 days later, car threw the "12V Battery needs replacement" error. Keep in mind I've been using the trunk kit using VCLeft for months with no issues. Took it to Tesla and they said that the error was due to aftermarket connections draining the battery and denied battery warranty, meaning I have to buy a new battery from them and have to wait for one to be ordered. However, I was skeptical because I actually took the 12V battery out and tested it and it showed as having normal charge. Still had the 12V error on the screen though, so the car couldn't install the Tesla firmware update I got this morning. Then I found this easy hard reset procedure (https://www.mountainpassperformance.com/tesla-model-3-hard-reset/) that effectively cleared the 12V error.

So long story short, I'll keep the trunk kit connected to VCLeft, disconnect the frunk kit from VCright, rewire it to the actual 12V positive like TeslaOffer instructed.
 

Skione65

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#69
@MrTofuDragon,

What’s your take on using the ‘under back seat power’? So as not to have to tap VCLeft. Will that throw any codes over time? HansShow says you can but I’m not so sure. Anyone (or yourself) with experience on this or that has done the install this way with no issues?

Ski
 

MrTofuDragon

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#70
@MrTofuDragon,

What’s your take on using the ‘under back seat power’? So as not to have to tap VCLeft. Will that throw any codes over time? HansShow says you can but I’m not so sure. Anyone (or yourself) with experience on this or that has done the install this way with no issues?

Ski
I haven't tapped anything into the red always on 12V under the passenger backseat myself, but have read elsewhere that it's a viable place to tap for higher voltage equipment like sound system Amplifiers. A known engineer guy in the Tesla community that has disassembled his car into pieces and found the other safe 12V connections noted this in a thread on Tesla motors club forums. Just do a Google search on "12volt trunk/frunk cable routing".

So yeah, go for it.
 

Franklin L

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#71
Tapping into the CAN bus is important, at least for the foot sensor. After an update a few months ago, my trunk opened as I was going over a speed bump. This required a firmware patch which the Tesla Offer guys got to me the same day. IMO, you get great customer service with these guys, so I have no regrets paying a bit more than elsewhere (the group buy thread for the other trunk guys didn’t look like everyone had a good experience).

Without tapping into the bus (like is being done elsewhere), you’re operating things by fooling the car into thinking the trunk is always closed. I’ve read some people with the non- Tesla Offer trunks had problems with their foot sensor because of that and from my experience, that makes sense.

For what it’s worth, I’ve not had any problems with subsequent firmware updates, but it’s probably worth testing things after an update for those of us who have the Tesla Offer trunks and get firmware updates early. You can do this by trying to open the trunk while you’re not in park.
 
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Franklin L

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#72
So long story short, I'll keep the trunk kit connected to VCLeft, disconnect the frunk kit from VCright, rewire it to the actual 12V positive like TeslaOffer instructed.
Glad I read this. I was about to install a dash cam at VCRight, since the trunk is using VCLeft. I’m not sure now where to get a constant power supply for the dash cam. Can I share VCLeft with the trunk?
 

MrTofuDragon

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#73
Glad I read this. I was about to install a dash cam at VCRight, since the trunk is using VCLeft. I’m not sure now where to get a constant power supply for the dash cam. Can I share VCLeft with the trunk?
You've probably already figured something out by now, but if the VCLeft for trunk connection is still working for you, I don't see why adding a dashcam to the same connection would be an issue.

However, I should note that since I last posted, I was still getting the 12V warning with just the trunk connected to VCLeft (when previously it worked for months without issue) so either Tesla changed something with V10 firmware that was more strict about VCLeft connections, or something else was going on with my car. So I decided to move my TeslaOffer trunk connection from VCLeft to the actual positive terminal on the 12V battery itself. In addition to that, I upgraded to a Ohmmu LifePo4 12V battery to fully leave all these 12V issues behind me (Ohmmu basically guarantees that it would be able to handle all these extra power draws). No issues for over 2 weeks now, and now I have a robust 12V that can handle anything else I want to connect to it.
 

Skione65

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#74
You've probably already figured something out by now, but if the VCLeft for trunk connection is still working for you, I don't see why adding a dashcam to the same connection would be an issue.

However, I should note that since I last posted, I was still getting the 12V warning with just the trunk connected to VCLeft (when previously it worked for months without issue) so either Tesla changed something with V10 firmware that was more strict about VCLeft connections, or something else was going on with my car. So I decided to move my TeslaOffer trunk connection from VCLeft to the actual positive terminal on the 12V battery itself. In addition to that, I upgraded to a Ohmmu LifePo4 12V battery to fully leave all these 12V issues behind me (Ohmmu basically guarantees that it would be able to handle all these extra power draws). No issues for over 2 weeks now, and now I have a robust 12V that can handle anything else I want to connect to it.
@MrTofuDragon,

Please keep us updated on the Ohmmu performance. (I.e. any 12V warnings and such down the road).

Ski
 

MrTofuDragon

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#75
Please keep us updated on the Ohmmu performance. (I.e. any 12V warnings and such down the road).

Ski
Will do. I chatted with Ohmmu customer support before making the purchase and they were the ones that assured me of their battery's robustness at handling extra loads as well as the compatibility (no error codes from the car). Could just be "marketing" talk, but they said adding extra load on the stock lead acid battery may cause power levels to fluctuate too much, which triggers the car thinking the battery is going bad... and their battery that is essentially lithium ion (lifepo4) generates a much smoother power output under load. But what sold me was their 4 year warranty that I verified even with these aftermarket parts installed, they would cover 100% in the event of battery issues.

So yeah, I'm pretty confident no further 12v messages will come up, but who really knows the future...
 
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Kimmo57

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#76
I started having intermittent problems with my Teslaoffer trunk and contacted them via Whats App. They were very helpful and in the end managed to find the cause of the problem: a wire in a connector wasn't pushed all the way in.
This is a wire in a bunch that is fed into the trunk lid and then one by one pushed into a connector body.
So, as thorough as I thought I were in fitting the kit, I wasn't thorough enough and it was my own fault. :rolleyes:

Their support and patience is second to none and I can highly recommend!
 

Perscitus

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#77
Will do.... pretty confident no further 12v messages will come up, but who really knows the future...
Indeed 0 issues with Ohmmu installed for a year now.

Temp ranges down to 5F and up to 110F. Sub 30/20F charging. Extended unplugged periods, full range of SoCs, 150kW supercharging sessions, L2 charging weekly.

Zero issues with updates, going from v9 to v10 builds, service centers, mobile service work, ScanMyTesla etc.

Clearly improved (read) reduced vampire drain and PUP bass response (all inputs, especially properly generated FLAC).
 

jmb4370

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#78
I finished installing the TeslaOffer Trunk Kit over the weekend, and while it works just fine, the lid latch does seem to make a lot of noise when it unlatches and then opens. I think there was a work around to making the latch quieter, but it has not come up in any recent searches. If anyone has the link to the fix, or can describe how to make the latch quieter, it would be most appreciated!
 

MrTofuDragon

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#79
I finished installing the TeslaOffer Trunk Kit over the weekend, and while it works just fine, the lid latch does seem to make a lot of noise when it unlatches and then opens. I think there was a work around to making the latch quieter, but it has not come up in any recent searches. If anyone has the link to the fix, or can describe how to make the latch quieter, it would be most appreciated!
Here you go, found the link on the other Tesla forum.

However, on mine the kinda loud sound when the trunk unlatches doesn't seem to come from the mechanism that they show being quieted in the video so I didn't do this suggested fix. If you end up doing it and notice a substantial difference in the loudness of the unlatch, please let us know.
 

jmb4370

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#80
@MrTofuDragon : Thanks for the link. I'll post once I have examined the latch mechanism more closely!

If anyone has one of these cabin auxiliary trunk switches that they don't intend to use, and would like to pass it along to me, please send a message. Thanks!