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Installing a Tekonsha Prodigy P2 Brake Controller in a Model X

ShawnA

Supporting Member
Nov 13, 2017
952
687
Edwardsburg, MI
Hi @ohmman ,

Does the 12 volt plus in the 7 pin connector work???
After mine was field serviced it works fine.
It only has power present when the car is "On."

There was a time in 2018 when it was disconnected...
Just wondering if the newer cars are back to having it connected...

Thank You,

Shawn
 

BM3B

“beaver”
Mar 8, 2019
790
948
Los Angeles, CA
Thank you @adelman for the excellent instructions, I was able to install a new P2 in my new X in about an hour, which included some child care time! I am excited to test it out with an Airstream rental this weekend. Right now I am just blue dot dot
 

jointed

Member
Aug 24, 2020
11
5
Cardiff by the Sea
I'm ready to publish the instructions as I feel they've been sufficiently validated.

http://www.adelman.com/model-x-brake-controller.pdf

Please do NOT copy or distribute the document, but rather the *link* to the document. I will update the copy behind this link as necessary.
Thank you for putting this together. I'm getting ready to install a P-3 in my X. Just checking that revision 1.03 was the last.
 

BM3B

“beaver”
Mar 8, 2019
790
948
Los Angeles, CA
Thank you @adelman for the excellent instructions, I was able to install a new P2 in my new X in about an hour, which included some child care time! I am excited to test it out with an Airstream rental this weekend. Right now I am just blue dot dot
@adelman unfortunately, my P2 did not work with my airstream trailer. I got all the necessary adapters. Tow mode worked, lights worked, but no active braking assist from P2. I don't know if it is a wiring issue (doubtful) or other hardware issue (faulty P2?). I don't want to take it all out to check. Any ideas from the pros?
 

ShawnA

Supporting Member
Nov 13, 2017
952
687
Edwardsburg, MI
Hi @BM3B ,

A basic check to see if it is connected to hopefully functional brakes would be
to press the brake pedal and look for a voltage reading in the display of the unit...

If you do not see a voltage, you will definitely not get any braking...

If you see voltage more steps are needed.
Has anyone in any vehicle made the brakes function???

Good luck,

Shawn
 

BM3B

“beaver”
Mar 8, 2019
790
948
Los Angeles, CA
Hi @BM3B ,

A basic check to see if it is connected to hopefully functional brakes would be
to press the brake pedal and look for a voltage reading in the display of the unit...

If you do not see a voltage, you will definitely not get any braking...

If you see voltage more steps are needed.
Has anyone in any vehicle made the brakes function???

Good luck,

Shawn
Thanks, no response when I press the brakes. The unit just shows “C”
 

ohmman

Plaid-ish Moderator
Feb 13, 2014
10,087
18,310
North Bay, CA
If the LED lights work but the controller doesn't seem to show voltage for braking, I would think that there might be a problem with the wiring of the brake controller to the vehicle. One of those wires (red lead) is supposed to be run to the cold side of the brake switch so that the Tekonsha recognizes that the vehicle is in a state of braking. If that wire isn't properly connected to either the brake controller or the far side of the wiring harness, you'll have this problem.
 
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BM3B

“beaver”
Mar 8, 2019
790
948
Los Angeles, CA
If the LED lights work but the controller doesn't seem to show voltage for braking, I would think that there might be a problem with the wiring of the brake controller to the vehicle. One of those wires (red lead) is supposed to be run to the cold side of the brake switch so that the Tekonsha recognizes that the vehicle is in a state of braking. If that wire isn't properly connected to either the brake controller or the far side of the wiring harness, you'll have this problem.
Thank you, I will check it out. I took my time on the crimps but maybe there is an issue. To test I should look for a voltage number when pressing the brake?
 
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ohmman

Plaid-ish Moderator
Feb 13, 2014
10,087
18,310
North Bay, CA
Thank you, I will check it out. I took my time on the crimps but maybe there is an issue. To test I should look for a voltage number when pressing the brake?
That is what I'd do. You'll see the .c. and when you brake, it'll change to a number (if you're hooked up to your Airstream).
 

ShawnA

Supporting Member
Nov 13, 2017
952
687
Edwardsburg, MI
Hi @BM3B ,

Go to your Airstream rental place or your dealer and ask to hook up
the harness to test.
Any trailer with electric brakes should work for your test...

Good luck,

Shawn
 
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Carlrich

New Member
Oct 22, 2020
3
0
Cincinnati
I am ready to buy a trailer brake controller. Read every word here and will install as suggested. Many thanks. I think I would want all the regen I can get when I lift from the throttle but want the trailer to brake when I touch the car brake. If the trailer brakes due to the car slowing from me lifting off the throttle then I give up regen. Is there a way to maintain regen and have the trailer brake when I brake? Can the P2/P3 do this for me?
thanks in advance
 

dmurphy

Buster: 11/25/14 - 6/20/21. So sorely missed.
Dec 7, 2018
3,656
4,894
New Jersey - Morris County
I am ready to buy a trailer brake controller. Read every word here and will install as suggested. Many thanks. I think I would want all the regen I can get when I lift from the throttle but want the trailer to brake when I touch the car brake. If the trailer brakes due to the car slowing from me lifting off the throttle then I give up regen. Is there a way to maintain regen and have the trailer brake when I brake? Can the P2/P3 do this for me?
thanks in advance

Not particularly. I wouldn’t worry about it. The safety of the trailer braking far outweighs the small regen loss. Mine definitely still regens, just with a longer stopping distance.

Can’t recommend the Tekonsha enough; it’s a quality control unit.
 
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maracucho97

New Member
Mar 25, 2021
2
0
Texas
I followed the excellent instructions but I'm having issues. The Tekonsha is not turning on even with the car turned on and in trailer mode. I used a multimeter and it looks like there is no power coming at all to the brake controller connector. I guess I need to put in a service request with Tesla. I can't think of any reason it's not providing power other than maybe a fuse and from what I read it seems like Tesla doesn't provide fuse diagrams for owners to check and replace fuses.
 

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