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Trailer electrical connector DOA on New MYP

GSP

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Dec 28, 2007
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Looking at the linked wiring diagram, trailers that are required to have a trailer breakaway system need 12 V power on pin 6 to keep the system’s 12 V battery charged. When the trailer breaks away, this 12 V battery applies the electric trailer brakes.

Perhaps this is leading to some of the confusion about the need for 12 V aux power on pin 6 for trailers with brakes. Trailers without a breakaway system don’t need it, and use pin 5 to control and activate their electric brakes, but trailers that also have a breakaway system need to have both pin 5 and pin 6 functional.

GSP
 
Looking at the linked wiring diagram, trailers that are required to have a trailer breakaway system need 12 V power on pin 6 to keep the system’s 12 V battery charged. When the trailer breaks away, this 12 V battery applies the electric trailer brakes.

Perhaps this is leading to some of the confusion about the need for 12 V aux power on pin 6 for trailers with brakes. Trailers without a breakaway system don’t need it, and use pin 5 to control and activate their electric brakes, but trailers that also have a breakaway system need to have both pin 5 and pin 6 functional.

GSP
Yes, but as I stated earlier, most brake controllers use the 12v to run the brake controller. And yes, you are correct, I should have said 6th pin not 7th. Most systems require the 6th pin in order to run the 5th pin, assuming your vehicle doesn't have a built-in brake controller (which Tesla's do not)
 
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GSP

Member
Supporting Member
Dec 28, 2007
2,665
1,020
Yes, but as I stated earlier, most brake controllers use the 12v to run the brake controller. And yes, you are correct, I should have said 6th pin not 7th. Most systems require the 6th pin in order to run the 5th pin, assuming your vehicle doesn't have a built-in brake controller (which Tesla's do not)
Yes, I agree there should be no problem powering a brake controller, which is installed in the tow vehicle, to 12-16 V power. The issue, I believe is trailers with a breakaway system. These systems require a 12 V battery mounted on the trailer. When the trailer breaks away from the tow vehicle, this battery applies the trailer brakes. The trailer’s 12 V battery needs to be maintained with a full charge, and that requires 12 V power on pin 6. 15-16 V power would likely overcharge the lead acid 12 V battery on the trailer, so a charger controller would need to be added to either the tow vehicle or trailer.

GSP
 
Uhhhhhh, Tesla STILL does not have a fix for this? My SC just informed me that they still do not have one. How in the world am I going to tow my trailer with proper electric brakes when I don't have power to the auxiliary on my trailer wiring harness? This is ridiculous!
I just installed the tekonsha p3 controller and it worked fine despite it having 15.5 volts. It passes electric brake line. The 12v line in the back is still dead, but it should work fine. I'll test with a rented trailer soon.
 

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