What is a idler pulley used for on ford bronco?

On a Ford Bronco, as with most vehicles, an idler pulley is a simple pulley that's part of the vehicle's accessory drive system. It doesn't directly drive anything (unlike a pulley on the alternator or power steering pump). Instead, it's used to:

* Change the direction of the belt: It helps route the serpentine belt around other pulleys, allowing the belt to efficiently drive multiple accessories. Without it, the belt might not be able to reach all the necessary components.

* Maintain belt tension: In some systems, the idler pulley is spring-loaded, helping to keep the correct tension on the belt. This prevents the belt from slipping or wearing prematurely.

Essentially, it's a crucial component for keeping the belt aligned and properly tensioned, ensuring all the accessories driven by that belt (alternator, power steering pump, air conditioning compressor, etc.) function correctly.