Today I have a Service Center appointment to have Tesla check my 7 pin trailer plug since I cannot get it to operate my LED bike rack lights. I have a 4-7 pin adapter that my 4 pin wiring harness plugs into. They called to tell me the installation of the 7 pin adapter voids Tesla's warranty. ( Not True )Service Guy tells me I need to get a "Tesla" 4-7 pin adapter which they don't sell. I have to pay them $110 to check the 7 pin plug is working correctly. I am so mad with Tesla Service Center right now. Has anyone with LED lights gotten them to work on a Model Y (April 2023 build).
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Model Y Trailer Plug Questions
- Thread starter MYPWR
- Start date
Watts_Up
Well-Known Member
Magnuson-Moss Act requires they prove the adapter caused any issue. But they were quick to suggest a 3rd party business in the area that might be able to help. If the car requires 7 pin to work I don't understand why. I know there is someone who has figured this out. I can wire a 7 pin harness but still only uses 4 of the 7 wires. If they said it need to see a level of resistance Like some cars do it would make sense and I could add a resistor to the wiring to trick it like you do on Audi and BMW.
You likely need an adapter that makes the LED lights compatible with the car. Something like this:
Though I'm sure I have seen smaller/cheaper ones before.
Though I'm sure I have seen smaller/cheaper ones before.
I already purchased that same one and it did not work. No brake or turn lights. Still waiting for SC to message me back on the 7 pin diagnostic testing results. If they can just confirm the trailer plug is working then I can keep working on what the Tesla computer is looking for to operate the lights properly.
So I am in a similar situation. I had the tow package installed at a service center and finally got around to using it. Im not getting any voltage from any of the pins on the 7 pin connector. I have my car headlights on and blinkers flashing and nothing. Tried it in trailer mode and not (I understand it shouldn’t make a difference).
I’m measuring the voltage using the -ve pin as the ground.
Is there anything else I should check before scheduling a service appointment?
Thanks OP for the heads up. I am trying to use a Thule rear cargo box and I hooked it up with a 7 pin to 4 pin connector. I’ll be sure to not mention that if I have to take it back. Nothing about that should affect the car though. And sorry about your situation. That’s absolute BS. Find a voltmeter and measure it yourself. You should be getting 12v. There’s a map of the pins on the pin cover.
2022 MY LR
I’m measuring the voltage using the -ve pin as the ground.
Is there anything else I should check before scheduling a service appointment?
Thanks OP for the heads up. I am trying to use a Thule rear cargo box and I hooked it up with a 7 pin to 4 pin connector. I’ll be sure to not mention that if I have to take it back. Nothing about that should affect the car though. And sorry about your situation. That’s absolute BS. Find a voltmeter and measure it yourself. You should be getting 12v. There’s a map of the pins on the pin cover.
2022 MY LR
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I may know more after picking up the car today. Tesla has made a mess of the trailer electrical issue.
I found these posts last night. The 12v power seems to have been disabled after Tesla switch the AUX battery to Li-Ion 16 volt. That should explain why the 12v pin is was dead.
Trailer 12V auxiliary power disabled in recent tow hitch-equipped Model Ys due to upgraded 12V Li-Ion battery - Drive Tesla (driveteslacanada.ca)
Tesla has a service bulletin covering the vehicles that had hitch retrofit missing the correct Controller.
https://teslamotorsclub.com/tmc/attachments/model-y-controller-pdf.951097/
Tesla owners discussing the issue.
Living with the 16v LV battery | Tesla Motors Club
Trailer electrical connector DOA on New MYP | Tesla Motors Club
Some may never have had the right module installed during the factory build.
Model Y: Tesla OEM Trailer Hitch DIY | Tesla Motors Club
When I connected the 4-7 pin adapter which I tried Curt with and without resistors. The dash displayed a Blue trailer which is good as it did not see a fault.
I found these posts last night. The 12v power seems to have been disabled after Tesla switch the AUX battery to Li-Ion 16 volt. That should explain why the 12v pin is was dead.
Trailer 12V auxiliary power disabled in recent tow hitch-equipped Model Ys due to upgraded 12V Li-Ion battery - Drive Tesla (driveteslacanada.ca)
Tesla has a service bulletin covering the vehicles that had hitch retrofit missing the correct Controller.
https://teslamotorsclub.com/tmc/attachments/model-y-controller-pdf.951097/
Tesla owners discussing the issue.
Living with the 16v LV battery | Tesla Motors Club
Trailer electrical connector DOA on New MYP | Tesla Motors Club
Some may never have had the right module installed during the factory build.
Model Y: Tesla OEM Trailer Hitch DIY | Tesla Motors Club
When I connected the 4-7 pin adapter which I tried Curt with and without resistors. The dash displayed a Blue trailer which is good as it did not see a fault.
It sounds like you’re in a better position than me. I have a 7 to 4 pin adapter with leds and I’d assume that would trip the trailer mode in the system … but no.
I have a dual LED light kit for my Rockymounts guiderail I built. Not my first bike rack led kit I built. Easy 4 wires with adapter works on every other car and truck but not this Tesla. If your car does not have the trailer module (link above) you won't get the trailer displayed on the screen. You need the trailer module. Why shouldn't the 12v pin #4 (red or black) work? It should lead you to question it may have something to do with the trailer connector not working. Don't give Tesla a way out of explaining why it doesn't work. Should be free fix under warranty. Use the service bulletin as your evidence that they need to fix your electrical connector. I am still waiting to hear back from the SC.
The connections 1, 2, and 4 are not required for trailer lights to work. Regulations do not require Backup Lights, Electric Brake Control, or 12v power. So 4 pin connectors are just fine.
The connections 1, 2, and 4 are not required for trailer lights to work. Regulations do not require Backup Lights, Electric Brake Control, or 12v power. So 4 pin connectors are just fine.
The car passed the trailer plug test at the Service Center. So I am back to figuring out what else it could be preventing the lights from working. I have ordered a Reese Tow Ready 20142 7-Way Flat Pin to 7-Flat Plug to Plug Adapter from Amazon. It’s a Lamp Out By-Pass for European Vehicles equipped cars. Amazon.com: Tow Ready 20142 7-Way Flat Pin to 7-Flat Plug to Plug Adapter, Regular : Automotive
I tested the connector with CURT 58271 7-Pin RV Blade Trailer Wiring Towing Vehicle Socket Tester. The Tesla plug is working! So now I will try the Reese Tow Ready 20142 later this week when it arrives.
Plugs I have tried and did not work.
CURT 57004 LED-Compatible 7-Way RV Blade Vehicle-Side to 4-Way Flat Trailer-Side Trailer Wiring Adapter
CURT 57003 LED-Compatible 7-Way RV Blade Vehicle-Side Trailer Wiring Adapter
I tested the connector with CURT 58271 7-Pin RV Blade Trailer Wiring Towing Vehicle Socket Tester. The Tesla plug is working! So now I will try the Reese Tow Ready 20142 later this week when it arrives.
Plugs I have tried and did not work.
CURT 57004 LED-Compatible 7-Way RV Blade Vehicle-Side to 4-Way Flat Trailer-Side Trailer Wiring Adapter
CURT 57003 LED-Compatible 7-Way RV Blade Vehicle-Side Trailer Wiring Adapter
Nothing is working.
Have a new solution will have to wait until 4-Pin Flat Tailgate Light Bar Signal Relay Box for Ford Super-Duty Pick-up up to 2018 with Tow Package BLIS arrives. Fingers Crossed. Will post results and pictures in a couple weeks.
So my first suggestion to anyone having problems with trailer lights is to get a 7 pin and 4 pin tester. Takes alot of guess work out. They are pretty cheap.
Now once you can verify the brake and turn signal test passes you are ready to move forward.
Low power 12v Red or Black on the Tesla Model Y does not work. See diagram above it is pin number 4. No power we will work around this.
The Tail Lamps pin number 7 in the diagram is on all the time while the 7 to 4 pin adapter is connected and the car is awake. We will use the Tail Lamps power to supply the 12 volts we need to fix this issue. I checked and it is 12.5 volts constant. Else we have a 12v cigarette outlet in the back cargo area to tap the 12v from if needed. The relay I am going to test in a few weeks needs that 12 volt power to make the turn and brake lights work.
Have a new solution will have to wait until 4-Pin Flat Tailgate Light Bar Signal Relay Box for Ford Super-Duty Pick-up up to 2018 with Tow Package BLIS arrives. Fingers Crossed. Will post results and pictures in a couple weeks.
So my first suggestion to anyone having problems with trailer lights is to get a 7 pin and 4 pin tester. Takes alot of guess work out. They are pretty cheap.
Now once you can verify the brake and turn signal test passes you are ready to move forward.
Low power 12v Red or Black on the Tesla Model Y does not work. See diagram above it is pin number 4. No power we will work around this.
The Tail Lamps pin number 7 in the diagram is on all the time while the 7 to 4 pin adapter is connected and the car is awake. We will use the Tail Lamps power to supply the 12 volts we need to fix this issue. I checked and it is 12.5 volts constant. Else we have a 12v cigarette outlet in the back cargo area to tap the 12v from if needed. The relay I am going to test in a few weeks needs that 12 volt power to make the turn and brake lights work.
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I have ordered this module:
https://www.truemods.com/4-pin-add-...tow-packageblind-spot-detection-accepsacp6001
This is supposed to work on the Tesla with LED trailer lights.
My dilemma is how to power the adapter.
This Trumods adapter requires 12 volt constant power. 15.5 volts is the power output at the trunk socket. My plan is to power this from the rear of the Model Y trunk socket. Since the socket outputs 15.5v I get a step down converter to 12 volts and hard wire it (tap) to the trunk socket wiring and add a second 12 volt socket. It will be there anytime I need a 12v power source. When I need to trailer I would plug the Trumods Adapter into the 12 volt socket.
https://www.truemods.com/4-pin-add-...tow-packageblind-spot-detection-accepsacp6001
This is supposed to work on the Tesla with LED trailer lights.
My dilemma is how to power the adapter.
This Trumods adapter requires 12 volt constant power. 15.5 volts is the power output at the trunk socket. My plan is to power this from the rear of the Model Y trunk socket. Since the socket outputs 15.5v I get a step down converter to 12 volts and hard wire it (tap) to the trunk socket wiring and add a second 12 volt socket. It will be there anytime I need a 12v power source. When I need to trailer I would plug the Trumods Adapter into the 12 volt socket.
SigRed12
Member
For what it’s worth with my 08/23 Fremont Y, I tried the OPT7 [Amazon.com] and one of the turn signals acted as if a bulb was out.
Ordered the CURT 57245 [Amazon.com] and it worked perfectly.
Ordered the CURT 57245 [Amazon.com] and it worked perfectly.
The wiring adapter for LED lights on the Tesla 16 volt system is assembled. It required a few parts to convert the 16v to 12v and allow the turn signals to function properly. To start I pluged in the 12v accessory to the trunk 16v outlet. Then plug the 4 pin inline to the LED lights and the 7 Pin adapter plug.
