Diagnose RV Starting and Chassis Power Issues

What happens here

The video begins with the creator explaining that his RV engine is cranking slowly and eventually fails to start. He notes that the 'house' power system (AC, fridge, microwave) is still functional, but the 'chassis' system (engine, dashboard, headlights) is completely dead. He attempted to use the 'merge switch' to connect the house batteries to aid the chassis battery, but this did not resolve the issue, indicating a more significant problem than just a low battery. He also mentions tightening a loose positive battery terminal, which also did not resolve the core problem.

Goal: Identify the symptoms of the RV's power problem and differentiate between chassis and house electrical systems.