Final answer:
Elizabeth may need to repair or replace the tensioner to get the belt tight again, as it retains proper tension on the engine's drive belts, ensuring that auxiliary components operate correctly.
Step-by-step explanation:
When Elizabeth notices that a rubber belt is not tight enough to move all the engine's auxiliary components, she may need to fix or replace the tensioner. The tensioner is responsible for maintaining the correct tension on the engine's drive belts. If the tensioner is faulty, the belt may become loose, leading to insufficient operation or slippage of the belt which drives essential components such as the alternator, water pump, power steering pump, air conditioner compressor, and possibly other accessories.
If she is unsure of how to proceed, Elizabeth should consult a professional mechanic to properly diagnose the issue and replace the tensioner if necessary. This would restore the adequate tension to the belt and allow the vehicle's engine components to function correctly.