Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

4SUPER9

2022 Model S
Jun 6, 2013
3,352
3,280
So Cal
I am creating this thread to discuss access to power for those who desire modifications to the 2021 refresh Model S, such as adding a radar detector, dashcams, additional LED lighting, etc. This is being already discussed in multiple different areas, but not consolidated anywhere. I inadvertently hijacked the Diagnostic Port Index thread, where there is a lot of good information in there, but has taken a tangent off the purpose of that thread. I am asking the Mods to move many of those posts over here. There is also good info in this radar detector thread. For full disclosure, I do not have my refresh yet. I am just gathering information. More importantly, I deserve zero credit for this, as I honestly just compiling information from the hard work of others. I love modding my cars and often ride the coattails of others.

Personally, I am interested in both switched and unswitched sources. Switched is great for radar detectors, as one example, which have no major use while not driving. I want unswitched for dashcams, which I would like active while parked. I may want some LED features always on as well, which I can turn off manually through a separate remote switch when I desire.

Important notes:
  • There is no fuse box in the refresh. There are electronic circuits managed by the CPU
  • Early reports showed that tapping into existing wiring can, but not necessarily, trigger all sorts of alerts.
  • There is no standard 12V battery in the refresh for direct access. There is a Li-ion battery that does not have traditional posts. This was my preference initially, where I would have added my own separate fuse box.
These are what 12V / power sources I have accumulated so far:
  • There is a cable in the driver’s lateral (outside) footwell behind the carpet that gives switched 12V access (thanks to @Hawkdriver for this discovery). It is also possible that this is in the passenger footwell as well (@Venom may have used this). These extra cables may be similar to the cable used for the tow package brake controller found on the X & Y (@Stewart ), and it is possible this $4.40 part from Tesla will allow an easy connection: BRAKE ECU ADAPTER (1072586-00- A). The part is not available online, so my guess is that you need to order it directly from Tesla. Proper fit has not yet been confirmed. The original intended purpose of this hidden connector is not clear. There is no known tow feature for the Model S, so maybe it is a left over from a similar wiring harness. Or, maybe something to do with ambient lighting upgrades.
  • There is indeed an OBD-II connector under the dash in the driver’s footwell, as has been in all prior Model S's, pre-refresh. This provides unswitched 12V access with pin 4 = ground, and pin 16 = 12V. There are all sorts of OBD-II connectors online that will allow you to tap into this, including some with built-in step-down to 5V.
  • As per the Diagnostic Port Index thread, there is a proprietary adapter hidden under the center wireless charging pad. In prior iterations of the Model S, this has been used for mods such as the lighted rear applique. This has switched 12V access. It requires a Maxwell adapter to either convert to OBD-II, or just to get access to switched power. I won't talk about this myself, as I have extremely limited knowledge of using this advanced port.
  • @rhuber accessed switched power for his radar directly from the front camera. I am waiting to hear back on exactly how he did this. No alerts were reported. Personally, I am a little concerned about access such a vital camera.
  • Finally, there is easy 12V access by plugging into the cigarette lighter adapter hidden in the center counsel.
Again, I am not an expert in this, and I apologize for any errors. I would love to hear others contribute to this thread.
 

4SUPER9

2022 Model S
Jun 6, 2013
3,352
3,280
So Cal
Someone on another thread is now saying that the cable in the footwell is NOT a trailer brake connector. If so, that part number may be incorrect. I may order one anyway, as I do not know what else may fit.
Here is a pic:

1632105594732.jpeg

@Bull
 
  • Like
Reactions: Robotpedlr
I wired in my Valentine 1 radar on my Plaid to the mirror / front camera housing. There is only one spot, it runs about 5-7v, its the red and black wire I believe on the 4 prong connector (has a purple and brown as well) located driver side under the rear view mirror main cover.. its a Very thin wire so you must be ultra delicate working with it. That is the only tappable line in that area.. all others including under headliner light connectors do not work or give a variable signal.

I have had the radar working for a week now.. However, today for the first time I have a car malfunction, adaptive suspension reduced, traction control reduced, steering reduced. I powered off the car and let it sit for 15min and it worked fine. I think I glitched the computer by hitting the brake as I was getting in the car causing multiple start ups to over lap (the AC, screen, and powertrain)... I do Not think it is associated with my radar tapping because its a front camera thing and all my cameras and such worked just fine and had no faults.. I also unplugged the radar to eliminate current draw and it didnt change the error so 99% they are unrelated... ***I will follow up again here with an Edit if it happens again so if you dont see an update here then do not worry....***

As far as im concerned its a done deal, works great, no issues and a good source.. The valentine runs on 5v+ per manual, so if your looking for a full 12v look elsewhere. I did find one 12v-14v line also to the interior camera but I believe it had major swings and although my V1 turned on, it did not like the power source for some reason and gave a wierd half lit screen on the radar with no control over functions
 

Bull

Chatting is great, just don't shoot the Bull.
Supporting Member
Oct 25, 2020
870
2,273
Tucson, AZ
Someone on another thread is now saying that the cable in the footwell is NOT a trailer brake connector. If so, that part number may be incorrect. I may order one anyway, as I do not know what else may fit.
Here is a pic:

View attachment 711643

@Bull
That was me. The connector could work just fine but there won't be a trailer connector in a model S. Hopefully the part mentioned does fit and makes an easy way to use those wires. I always prefer a connector over tapping a wire.
 
  • Like
Reactions: Robotpedlr

4SUPER9

2022 Model S
Jun 6, 2013
3,352
3,280
So Cal
I wired in my Valentine 1 radar on my Plaid to the mirror / front camera housing. There is only one spot, it runs about 5-7v, its the red and black wire I believe on the 4 prong connector (has a purple and brown as well) located driver side under the rear view mirror main cover.. its a Very thin wire so you must be ultra delicate working with it. That is the only tappable line in that area.. all others including under headliner light connectors do not work or give a variable signal.

I have had the radar working for a week now.. However, today for the first time I have a car malfunction, adaptive suspension reduced, traction control reduced, steering reduced. I powered off the car and let it sit for 15min and it worked fine. I think I glitched the computer by hitting the brake as I was getting in the car causing multiple start ups to over lap (the AC, screen, and powertrain)... I do Not think it is associated with my radar tapping because its a front camera thing and all my cameras and such worked just fine and had no faults.. I also unplugged the radar to eliminate current draw and it didnt change the error so 99% they are unrelated... ***I will follow up again here with an Edit if it happens again so if you dont see an update here then do not worry....***

As far as im concerned its a done deal, works great, no issues and a good source.. The valentine runs on 5v+ per manual, so if your looking for a full 12v look elsewhere. I did find one 12v-14v line also to the interior camera but I believe it had major swings and although my V1 turned on, it did not like the power source for some reason and gave a wierd half lit screen on the radar with no control over functions
Am I correct to assume this is a switched source? My radar is a installed Escort Passport 9509ci , so I need access in the footwell. But, I could use constant on for my Blackvue. For now, I am planning to run a wire up from the footwell to the mirror.
That was me. The connector could work just fine but there won't be a trailer connector in a model S. Hopefully the part mentioned does fit and makes an easy way to use those wires. I always prefer a connector over tapping a wire.
Yep. I have tapped plenty of wires in several Tesla’s, and each time, I’m terrified of screwing up something bad. Quick disconnect is far cleaner, and safer.
 

Robotpedlr

Member
Supporting Member
Dec 17, 2017
727
1,258
Seattle
That was me. The connector could work just fine but there won't be a trailer connector in a model S. Hopefully the part mentioned does fit and makes an easy way to use those wires. I always prefer a connector over tapping a wire.
Is that connector to a switched 12v source? I havent taken delivery of my MS yet, but am trying to plan for AL Priority radar add on… would also prefer a connector type instead of wire tap if possible. May also look at option of running to the 12v accessory plug in console if hidden enough.
 
Am I correct to assume this is a switched source? My radar is a installed Escort Passport 9509ci , so I need access in the footwell. But, I could use constant on for my Blackvue. For now, I am planning to run a wire up from the footwell to the mirror.

Yep. I have tapped plenty of wires in several Tesla’s, and each time, I’m terrified of screwing up something bad. Quick disconnect is far cleaner, and safer.
It is a switched source.. When I enter the car it turns the radar on, otherwise when locked away it is off.. I will agree its terrifying to tap into but I have done dozens of radar installs and pretty much have been tapping for 20 years. The trick is to have a fresh razor blade, slice a bit of the skin off the wire, do the same to the v1 wire, touch em together, then intsert the alligator tap to lock it all in and then black electrical tape to freeze it in place so it will not wiggle. Perhaps im just cut out to be a surgeon lol as I do agree it takes a Very careful hand and delicacy.

The tesla tap was by far the thinnist and most nerve wracking of all Ive ever done but once done and taped up, its solid and works great and you can stuff all the extra wiring and V1 connections into the roof liner along the windshield, plenty of space.. I also stick my radar direct to the right side of the mirror at the top of the windshield / headliner so its always out of the way, stays hidden, and no wires anywhere or bulk in my vison.
 
Last edited:
Someone on another thread is now saying that the cable in the footwell is NOT a trailer brake connector. If so, that part number may be incorrect. I may order one anyway, as I do not know what else may fit.
Here is a pic:

View attachment 711643

@Bull
The Tesla trailer brake ECU adapter (1072586-00-A) definitely fits this connector. Attached picture is the ECU adapter plugged into the connector in the footwell. I’m seeing 12V switched power from the red wire. Black is chassis ground.
 

Attachments

  • 775362DD-8587-49D3-8212-705D7A201C11.jpeg
    775362DD-8587-49D3-8212-705D7A201C11.jpeg
    399.9 KB · Views: 430
Last edited:

4SUPER9

2022 Model S
Jun 6, 2013
3,352
3,280
So Cal
The Tesla trailer brake ECU adapter (1072586-00-A) definitely fits this connector. Attached picture is the ECU adapter plugged into the connector in the footwell. I’m seeing 12V switched power from the red wire. Black is chassis ground.
This is perfect! Thanks. Glad that they have the standard colored wires on it too (missed that on your prior photos).
 

Bull

Chatting is great, just don't shoot the Bull.
Supporting Member
Oct 25, 2020
870
2,273
Tucson, AZ
The Tesla trailer brake ECU adapter (1072586-00-A) definitely fits this connector. Attached picture is the ECU adapter plugged into the connector in the footwell. I’m seeing 12V switched power from the red wire. Black is chassis ground.
That is great news. Thank you. I'm still a little concerned what that connector is actually for (the one in the car, not the trailer brake adapter). I will still use it for my dashcam until I find a reason not to though.
 
Last edited:

4SUPER9

2022 Model S
Jun 6, 2013
3,352
3,280
So Cal
That is great news. Thank you. I'm still a little concerned what that connector is actually for (the one in the car, not the trailer brake adapter). I will still use it for my dashcam until I find a reason not to though.
Are you are you want to use a switched source for your dahcam? It will be off when parked. I am going to use the OBD-2 connector which is always on. I am buying an OBD splitter, which should split the OBD into two access sources. I will cut off the two OBD ends, and crimp quick connectors on the wires I need for 12v. Plug ‘n play for two different sources.

(I am trying to post a link to the splitter, but keep getting an error message. I’ll try later from my laptop)
 
Last edited:

Bull

Chatting is great, just don't shoot the Bull.
Supporting Member
Oct 25, 2020
870
2,273
Tucson, AZ
Are you are you want to use a switched source for your dashcam? It will be off when parked. I am going to use the OBD-2 connector which is always on. I am buying an OBD splitter, which should split the OBD into two access sources. I will cut off the two OBD ends, and crimp quick connectors on the wires I need for 12v. Plug ‘n play for two different sources.

(I am trying to post a link to the splitter, but keep getting an error message. I’ll try later from my laptop)
My Thinkware u1000 actually prefers both switched and unswitched so it can go into a different mode when the car is parked. I'll try to grab the OBD unswitched too while I am in tha area.
 

4SUPER9

2022 Model S
Jun 6, 2013
3,352
3,280
So Cal
My Thinkware u1000 actually prefers both switched and unswitched so it can go into a different mode when the car is parked. I'll try to grab the OBD unswitched too while I am in tha area.
FYI, the one time my car got hit, I was parked. Sentry mode was off for a software update, and I forgot to turn it back on.
Here is the OBD adapter I bought. Cheap, and I can easily access all the wires, plus have another set for another project. It arrives tomorrow, so I will test it out soon on my current S.
 
  • Like
Reactions: Bull

4SUPER9

2022 Model S
Jun 6, 2013
3,352
3,280
So Cal
I just came back from my local service center. I asked for the part, they pulled it off the shelf, and tried to sell it to me. That's were it failed. Apparently, every part must be attached to a VIN. I used my current VIN, and the computer failed to process it. He tried every permutation. He then realized that this part does not fit my current MS. He said he would hold it for me until I had a proper VIN. Ugh!
 

Robotpedlr

Member
Supporting Member
Dec 17, 2017
727
1,258
Seattle
I just came back from my local service center. I asked for the part, they pulled it off the shelf, and tried to sell it to me. That's were it failed. Apparently, every part must be attached to a VIN. I used my current VIN, and the computer failed to process it. He tried every permutation. He then realized that this part does not fit my current MS. He said he would hold it for me until I had a proper VIN. Ugh!
I think it may be a model X connector part number... so I am sure you can google a Mode X for sale and use the VIN to buy the part..? I may try later this week when I am near a TSC.
 

4SUPER9

2022 Model S
Jun 6, 2013
3,352
3,280
So Cal
As an update, I used my friend's VIN from his X and I had no issue getting the part. It is already crimped and ready to have my radar plugged in. I just need a car now!! :D
I also showed him the screenshot where it says "no VIN" but he was stuck, as every purchase must be attached to a VIN (as far as he knows). He was very cool and really tried to find a work-around.

Is that connector to a switched 12v source? I havent taken delivery of my MS yet, but am trying to plan for AL Priority radar add on… would also prefer a connector type instead of wire tap if possible. May also look at option of running to the 12v accessory plug in console if hidden enough.
No need to run from the accessory plug when can run a cable from the footwell. Much, shorter run, and we now have two options: switched from that snap-in connector, or unswitched from the OBD. Both in the same area and both plug-n-play.
 

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top