Before using stabilizer jacks, what component must operate properly on the fifth wheel?

The landing gear must operate properly before using stabilizer jacks on a fifth wheel because it provides the initial support and stability for the trailer. Properly functioning landing gear allows the unit to be level and secure before stabilizer jacks are deployed, ensuring that the weight is evenly distributed and reducing the risk of tipping or movement when setting up.

If the landing gear is not working correctly, it could lead to an unstable setup, which could compromise safety and lead to issues when stabilizer jacks are used. Ensuring the landing gear is operational is crucial for providing a solid foundation for the entire trailer. The other components mentioned, while important for the overall operation and safety of the vehicle, do not directly relate to the stability and support that the landing gear provides at the outset of setting up a fifth wheel.