What is the recommended action when preparing for RV brake testing?

When preparing for RV brake testing, pulling the breakaway cable is a critical action because it ensures that the braking system is effectively operating as intended. The breakaway cable is designed to activate the trailer's electric brakes in the event that the trailer becomes disconnected from the tow vehicle. By engaging this cable during a brake test, the operator can assess the functionality of the braking system and ensure that it will operate reliably should an emergency disconnection occur.

This action is particularly important because it allows for immediate feedback on the integrity of the brake system, confirming that it will engage properly to prevent accidents. Understanding the role of the breakaway cable is essential to ensuring safety while towing, making this the correct action in the context of RV brake testing.