As we learned more info from a different anonymous reader of our site, we found out that Tesla will probably introduce "Trailer Mode" in the future either through custom orders ( maybe thru App purchase) or Free OTA software update.
Here we go with some EXCLUSIVE details of this Trailer Mode feature for Tesla Model Y:
Regulations require all trailers to be equipped with tail lights, brake lights, side marker lights, and turn signals. To provide power for trailer lighting, a built-in 7 pins wiring connector is provided near hitch support's wiring plugs for most types trailers. Plugging in trailer wiring into the Model Y electrical connector automatically engages Trailer Mode.
And here is more details about steps to connect a brake controller:
The maximum trailer weight (including all cargo and additional equipment), and the trailer tongue weight depend on the number of occupants in your vehicle and the tires being used. The maximum towing capacity and trailer tongue weight must never exceed the following:
5 or Fewer Occupants
Maximum Towing Capacity: 3200 lbs (1451 kg) *
Maximum Tongue Weight: 320 lbs (145 kg)*
*You must operate within the speed limitations of your trailer and tires. Always obey posted speed limits and local regulations regrading speed.