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The secret Frunk opener thing

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EVer Hopeful

Active Member
Jul 7, 2021
1,924
1,559
Texas
I read the User Manual before I got the vehicle, but tbh, I've already forgotten a lot of it and need to give it another go. Yesterday I read a thread that reminded me about the way to open the frunk with an A23 12v battery, so of course I had to try it - I mean open the hatch, not the actual frunk

When I got the cover off, I saw both terminals were held on to a post (maybe this is an 'upgrade' as YT videos suggested only one would be held there and you'd have to go fishing for the other. Whatever). Here's a pic and here's my question:

Does it matter if those two terminals touch? Because if it does, then this is a pretty p1ss poor set up and how can it not matter if they're connected to the electrical system?

My other question (and I'll RTFM again to see if it has the answer) is: Does it matter which way you pout the A23 battery? Because if it does, then this is a pretty p1ss poor set up etc etc

20220509_165912.jpg
 
IIRC those contacts simply allow access to 'jump' the car by providing power to the computer system in the event that the 12V battery dies. It doesn't actually open the frunk, rather it powers the car's computer system so it can then function.

As far as whether those contacts should touch, I would assume no.

Edit - incorrect info. Crossed out
 
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IIRC those contacts simply allow access to 'jump' the car by providing power to the computer system in the event that the 12V battery dies. It doesn't actually open the frunk, rather it powers the car's computer system so it can then function.
Nope, you can't "jump" the car with those. They are only to open the frunk, so that you can get to the jump points.
 
Nope, you can't "jump" the car with those. They are only to open the frunk, so that you can get to the jump points.
Thanks for the correction. I found this web site. Do you know where it describes this in the manual? I looked and couldn't find it anywhere.

Seems like a bit of a security risk. Anyone can easily pop the frunk with just a 12V battery.
 
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Yesterday I had the Auto Frunk installed on my Model Y, so that the Frunk opens/closes automatically whenever I tap the Frunk Open button either in the car or on my phone app. (Really nice mod)

While doing the installation, the installer called me over and showed me that my car didn't have these wires located behind the cap! He had to spend about 10-12 minutes using a long metal rod with a hook at the end, to find and fish the wires from where they were, to locate them where they were SUPPOSED to be!I would have been up a creek if my battery died, and I removed the cap expecting to find two wires, only to discover they weren't there!

Not really part of the "Auto Frunk" installation, but he was nice enough to spend the time to make sure the wires were where they should have been! (I didn't even realize what that cap was for before yesterday)
 
Well this is a bugger


The book (thanks for the page number) says: "Depending on production date, either the positive or negative terminal may be attached to the tow eye cover."

Mine have both on there


The book also says: "Connect the low voltage power supply's red positive (+) cable to the red positive (+) terminal. 5. Connect the low voltage power supply's black negative (-) cable to the black negative (-) terminal"

Mine are both black :(


I wish I'd not looked now
 
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Well this is a bugger


The book (thanks for the page number) says: "Depending on production date, either the positive or negative terminal may be attached to the tow eye cover."

Mine have both on there


The book also says: "Connect the low voltage power supply's red positive (+) cable to the red positive (+) terminal. 5. Connect the low voltage power supply's black negative (-) cable to the black negative (-) terminal"

Mine are both black :(


I wish I'd not looked now
Might be interesting to put a voltmeter across those terminals and have someone ask the frunk to open. At the very least you could determine which is supposed to be positive. As an alternative theory, maybe they have four sturdy diodes in place(bridge rectifier) so the polarity doesn't matter. That might be an extra-plausible theory if they don't want the motor to actually see 12V from the A23(each diode will have 0.6V voltage loss, so the delivered voltage will be 10.8V, since a bridge rectifier only uses two of the four diodes at a time)
 
Might be interesting to put a voltmeter across those terminals and have someone ask the frunk to open. At the very least you could determine which is supposed to be positive. As an alternative theory, maybe they have four sturdy diodes in place(bridge rectifier) so the polarity doesn't matter. That might be an extra-plausible theory if they don't want the motor to actually see 12V from the A23(each diode will have 0.6V voltage loss, so the delivered voltage will be 10.8V, since a bridge rectifier only uses two of the four diodes at a time)
I was going to suggest the same thing. I handing thought about the possibility of a rectifier.

If all it does is provide power to the latch motor my guess is it’s directly wired. If that’s the case one of the leads should be grounded. You would probably also see the voltage go up on the positive lead when you open the trunk.
 
So, is this the correct procedure for dead 12v battery:

1. A23 battery to terminals behind right bumper towhook cover, opens frunk.

2. Remove large cover from frunk (air intake and windshield wiper on it) to expose 12v battery and jumper it from
the USB jump starter. AFAIK there is no way to get inside the car even after frunk is open without jumping the 12v
battery.

Does anyone know how to get a frunk LED USB power takeoff to allow keeping the jump starter powered in frunk?
I am planning on keeping an A23 inside behind the bumper cover, but would like to have the starter in frunk.

Thank You
 
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So, is this the correct procedure for dead 12v battery:

1. A23 battery to terminals behind right bumper towhook cover, opens frunk.

2. Remove large cover from frunk (air intake and windshield wiper on it) to expose 12v battery and jumper it from
the USB jump starter. AFAIK there is no way to get inside the car even after frunk is open without jumping the 12v
battery.

Does anyone know how to get a frunk LED USB power takeoff to allow keeping the jump starter powered in frunk?
I am planning on keeping an A23 inside behind the bumper cover, but would like to have the starter in frunk.

Thank You
There is really no need or advantage to constantly charging a lithium ion jump starter. Just plug in the jump starter to charge every 4 or 5 months and the jump starter will hold the charge over the interim months.

I don't leave the jump starter in my Model Y frunk over to the summer as I feel the heat is not good for the long term health of the jump starter battery. I carry a 9 volt battery and leads with alligator clips separately when I am away and store the jump starter in the frunk in case needed.

When I am home Sentry mode is Off; If the 12V battery fails while my Model Y is parked at home I can use the jump starter to open the frunk. (I don't regularly store the jump starter in the frunk unless taking a trip.) When not parked at home Sentry mode is active. When Sentry mode is active the Tesla vehicle remains awake, powering the 12V systems. If the 12V battery fails while away from home I should still be able to unlock, drive the Model Y.
 
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I have a lot of battery powered devices that go unused for extended periods of time such as travel headphones, pool speakers, camera batteries, etc. I set a quarterly reminder in my iPhone to charge them all, including the jump starter.

I do leave my jump starter in the car all of the time, but my car lives in garage.
 
So I had my 12v die. I'm 1500km from the shop. Ordered a battery from Tesla Vancouver, they don't ship. Had to have my nephew go pick it up and ship it to me.

I opened the trunk removed the dead 12v. Place it on my bench. Go open the box, it's the wrong battery. Put my tools away, it starts to rain so I close the frunk. As I hear the click. I realized I've the dead 12 disconnected and not in the car.

So my question is.


How can I open the Frunk with no 12v installed?