After lowering the landing gear when uncoupling a trailer, what should you do next?

When lowering the landing gear after uncoupling a trailer, the next step is to disconnect the air and electrical connections and stow them. This is important because the air and electrical lines are crucial for the operation of the trailer's braking and lighting systems, and properly disconnecting them ensures that there’s no potential for damage or accidental engagement while the trailer is not connected to the tractor.

Stowing these connections correctly helps in maintaining their condition and prevents any trip hazards or environmental exposure that could cause damage. Properly handled connections also lay the foundation for safe and efficient future coupling.

While testing trailer brake lights, applying the tractor protection valve, or lowering the fifth wheel are important steps in the overall process of handling a trailer, they do not come immediately after lowering the landing gear in the uncoupling sequence. The focus should be on safely managing the air and electrical connections first to avoid issues.