Model Y purchased 12/31/23 Trailer / Tow Hitch wiring connector

[OZesati]

I got my model Y months ago. Installed an aftermarket Eco hitch / trailer hitch. I’m trying to connect the seven pin wiring harness. Does anyone know what these wires represent?

Using volt meter, I get 14volts touching black and red. 12 volts touching black and green, nothing on touching black and blue.

Turn on lights and blinkers, still nothing on blue.

Black looks to be ground. Red looks to be 12volt. Not sure what green is.

How can I tap into this connector and rear lights to get all 7 pins working. 12v, taillights, reverse lights, left turn, right turn, ground, and electric brakes?

 

[ewoodrick]

I got my model Y months ago. Installed an aftermarket Eco hitch / trailer hitch. I’m trying to connect the seven pin wiring harness. Does anyone know what these wires represent?

Using volt meter, I get 14volts touching black and red. 12 volts touching black and green, nothing on touching black and blue.

Turn on lights and blinkers, still nothing on blue.

Black looks to be ground. Red looks to be 12volt. Not sure what green is.

How can I tap into this connector and rear lights to get all 7 pins working. 12v, taillights, reverse lights, left turn, right turn, ground, and electric brakes?

Why not ask Ecohitch?

 

[rotarypower101]

I got my model Y months ago. Installed an aftermarket Eco hitch / trailer hitch. I’m trying to connect the seven pin wiring harness. Does anyone know what these wires represent?

Using volt meter, I get 14volts touching black and red. 12 volts touching black and green, nothing on touching black and blue.

Turn on lights and blinkers, still nothing on blue.

Black looks to be ground. Red looks to be 12volt. Not sure what green is.

How can I tap into this connector and rear lights to get all 7 pins working. 12v, taillights, reverse lights, left turn, right turn, ground, and electric brakes?

I think that plug is meant to plug into the Tesla trailer module, and the trailer module breaks out the trailer functionality?
IIRC, that will plug will probably be a CAN signal and power for both trailer brakes and +12V aux on 12VLV equipped models .

There are also aftermarket modules that tap into the existing lighting.

 

[OZesati]

Why not ask Ecohitch?

Ecohitch won't help with this. They'll try and sell you an aftermarket wiring harness that does not use this connector.

 

[Moloe]

Ecohitch won't help with this. They'll try and sell you an aftermarket wiring harness that does not use this connector.

I had the same issue thinking I would just multimeter my way to fit an aftermarket 7pin trailer but couldn't figure out the wiring- I asked the Ecohitch guy on Amazon for a wiring diagram and they are taping into the rear lights (not through that new Molex plug)

I will be eager to know if anyone has a wiring diagram connecting this...

to this...

I was thinking once I get the wiring diagram we can just re-pin the wires into the old Molex 16 or 20pin below since I cant find the new one on sale (unless Im missing something)... then mark it up to $200 on Amazon ( $30 for TMC

Some deets on my ModelY: LR Austin 11/23 Build VIN 198k (not structural pack so it still has the BUS connection under the center console)

 

[MYPHW4]

I think that plug is meant to plug into the Tesla trailer module, and the trailer module breaks out the trailer functionality?
IIRC, that will plug will probably be a CAN signal and power for both trailer brakes and +12V aux on 12VLV equipped models .

There are also aftermarket modules that tap into the existing lighting.

I believe you are correct. The new hitch receiver Rev G has a new controller unit that enables the trailer lights. I installed the Rev G hitch receiver myself and my trailer lights would not operate. I found the only way to enable the trailer lights with this module installed is to update the software for trailer mode, then reinstall the latest firmware (this step must be performed). I had Tesla Service enable trailer mode, but when I got home my lights still did not operate even though I could toggle trailer mode on my model y screen. I found an option to reinstall the software in Service Mode and this allowed my trailer lights to operate. I assume Tesla service did not perform this operation as I'm sure this isn't documented. I have a thread that discusses my experience with a diy oem hitch install and then getting the trailer lights to operate.

Model Y HW4 with OEM Tow Hitch Installed

 

[OZesati]

I ended up using the below wiring harness and tapping into the 14-volt wiring on existing noted tesla connector on previous picture. Black wire on Curt harness is hot, going to provided fuse, and then into tesla's red wire (hot) shown on the connector. The connector wires go into cabin as shown on picture and that's where I used t-tap to tap into tesla red wire. Did the same for left/right signal, brake light, and taillights - tap in directly to tesla's rear light wires. The ground white wire on Curt harness was bolted to existing bolt as shown. All checked out and working properly.

Tesla wiring:
Gray - Brakes
Yellow - Left Blinker
Red - Tail Lights

CURT 59236 Weather-Resistant Multi-Function Splice-in Trailer Taillight Converter Kit, 4-Pin Wiring Harness​