Inspect belts for cracks, fraying, wear and oil. If necessary, replace.
Inspect drive belt deflection or tension at a point on the belt midway between pulleys.
Check belt tension using belt tension gauge (BT 3373-F or equivalent).
Inspect drive belt deflection or tension when engine is cold. Adjust if belt deflection exceeds the limit or if belt tension is not within specifications.
Drive belt tension can also be checked at other points on the belts.