Tesla App Update Reveals Upcoming Trailer Light Test Feature

Trailer light test spotted in Tesla app 4.55.5

Tesla’s latest mobile app update reveals an upcoming tool to simplify towing. In app version 4.55.5, Tesla added a new text string that points to a future ability to test trailer lights directly from a smartphone.

Solving a common towing headache

Anyone who frequently tows a boat, camper, or utility trailer knows the pre-trip light check is required for safety and compliance. Verifying that the trailer’s brake lights, running lights, and turn signals are synchronized with the tow vehicle has typically been a two-person task: one person presses the brake and activates the indicators while the other confirms the lights at the rear.

For solo drivers, this often means checking only certain functions, like turn signals, or resorting to workarounds such as propping up a phone camera to see whether all lights are working.

Embedding a trailer light test in the Tesla app would let an owner stand behind the trailer and use the phone to quickly verify the lights.

The code hint

The upcoming feature was identified by examining the source of Tesla app version 4.55.5. A phrase in the app, MOBILE_APP_FEATURE_TRAILER_LIGHT_TEST, was noted by @Tesla_App_iOS.

Tesla frequently updates its mobile app to lay the groundwork for future vehicle features, and backend code strings often indicate functionality being prepared or tested.

Status

A dedicated trailer light testing mode is not yet available in Tow Mode.