Hello to Model X owners with Model X manufactured on or after March 6, 2018
and no power to the aux pin of the 7 way trailer connector,
I purchased a Model X-100D on February 2, 2018 for delivery March 22 of 2018.
I was fortunate that with a build date of March 6, 2018 I got the new MCU.
Getting ready for the trailer season, I purchased and installed a Prodigy P3 brake controller.
Performing due diligence before trailering, I used a common LED tester to assure all of the proper
voltages and signals were delivered to the 7 pin trailer harness.
I have shown a picture of the tester below.
All pins functioned as designed except the 12V aux pin.
No voltage was being delivered to the 12V aux pin.
I tow a utility trailer that uses the 12V aux power to recharge the breakaway battery and to
power small lights in the trailer.
I had a mobile service visit and we corrected the problem.
Apparently on or around March 6, 2018 there was an engineering change on the wiring regarding the trailer
harness.
As we looked at the short harness to the 7 pin connector, we noticed that the red supply wire from the car
was at the opposite end of the connector to the trailer...
The harness in the bottom picture is "as delivered."
The service technician moved the red wire in the harness to the other end of the connector
where the blue plug is shown and now there is power.
He installed the blue plug into the position where he removed the red wire.
The trailer harness to the 7 pin is Tesla part 1046032-00-C
The harness in my car was dated 11-14-2017.
I do not know if there was supposed to be a new revision of the 7 pin harness that I did not get
but moving the red wire to the other end of the connector fixed my issue.
One helpful detail: The 12V aux pin is supplied by a 15 Amp fuse number F131 in the frunk.
Another detail: There is a Fuse in the Aux box by the right foot of a right hand drive car
fuse F308 Jcase 30 Amp.
Yet another note - The 12V aux power is only supplied when the car is in DRIVE or another selection
where the High Voltage bus is active!!!
So, in an unattended car that is off there will be no power to the 12 V aux pin.
Enjoy,
Shawn
and no power to the aux pin of the 7 way trailer connector,
I purchased a Model X-100D on February 2, 2018 for delivery March 22 of 2018.
I was fortunate that with a build date of March 6, 2018 I got the new MCU.
Getting ready for the trailer season, I purchased and installed a Prodigy P3 brake controller.
Performing due diligence before trailering, I used a common LED tester to assure all of the proper
voltages and signals were delivered to the 7 pin trailer harness.
I have shown a picture of the tester below.
All pins functioned as designed except the 12V aux pin.
No voltage was being delivered to the 12V aux pin.
I tow a utility trailer that uses the 12V aux power to recharge the breakaway battery and to
power small lights in the trailer.
I had a mobile service visit and we corrected the problem.
Apparently on or around March 6, 2018 there was an engineering change on the wiring regarding the trailer
harness.
As we looked at the short harness to the 7 pin connector, we noticed that the red supply wire from the car
was at the opposite end of the connector to the trailer...
The harness in the bottom picture is "as delivered."
The service technician moved the red wire in the harness to the other end of the connector
where the blue plug is shown and now there is power.
He installed the blue plug into the position where he removed the red wire.
The trailer harness to the 7 pin is Tesla part 1046032-00-C
The harness in my car was dated 11-14-2017.
I do not know if there was supposed to be a new revision of the 7 pin harness that I did not get
but moving the red wire to the other end of the connector fixed my issue.
One helpful detail: The 12V aux pin is supplied by a 15 Amp fuse number F131 in the frunk.
Another detail: There is a Fuse in the Aux box by the right foot of a right hand drive car
fuse F308 Jcase 30 Amp.
Yet another note - The 12V aux power is only supplied when the car is in DRIVE or another selection
where the High Voltage bus is active!!!
So, in an unattended car that is off there will be no power to the 12 V aux pin.
Enjoy,
Shawn