How to diagnose trailer lights/brake not working

[Bikertodd]

I have a June Model Y with factory trailer hitch and just tried to hook up my trailer yesterday. I am using a 7-pin to 4-pin adapter. I have no lights on the trailer. I used my voltmeter to look for some voltage on the 7-pin connector and I get 0.00 volts everywhere I look. The service guy at my local center told me that I can't use a voltmeter to check because basically, the car is smart and looks to see that a trailer is connected.

Does anyone know of a way to test the 7-pin connector, so I can be more confident that it is the car's problem and not me or my trailer. I have an appointment to bring my car in next week, but I don't want to embarrass myself if it is my problem. I am about to hook up the trailer to my other car to verify that the trailer is ok.

 

[glide]

I have a June Model Y with factory trailer hitch and just tried to hook up my trailer yesterday. I am using a 7-pin to 4-pin adapter. I have no lights on the trailer. I used my voltmeter to look for some voltage on the 7-pin connector and I get 0.00 volts everywhere I look. The service guy at my local center told me that I can't use a voltmeter to check because basically, the car is smart and looks to see that a trailer is connected.

Does anyone know of a way to test the 7-pin connector, so I can be more confident that it is the car's problem and not me or my trailer. I have an appointment to bring my car in next week, but I don't want to embarrass myself if it is my problem. I am about to hook up the trailer to my other car to verify that the trailer is ok.

If you have a lithium 12V battery, my understanding is the trailer lights are disabled because Tesla cannot figure out how to get them to work.

That’s right. They sell you a tow package which renders you unable to tow.

 

[Bikertodd]

The trailer lights work fine on my other car, so there must be a problem in the Tesla or the adapter (unlikely).

 

[Bikertodd]

If you have a lithium 12V battery, my understanding is the trailer lights are disabled because Tesla cannot figure out how to get them to work.

That’s right. They sell you a tow package which renders you unable to tow.

Those news stories about the problems with the new Li-ion batteries said that the problem was only supposed to be with the 12V auxiliary power. The blinkers and brakes were supposed to still work.

 

[glide]

Those news stories about the problems with the new Li-ion batteries said that the problem was only supposed to be with the 12V auxiliary power. The blinkers and brakes were supposed to still work.

I don’t think so. Others have had the same issue. Search the forum.