Open the hood on the 1999 Dodge Caravan.
Locate the round adjustment pulley on the lower left hand side of the alternator. Loosen the lock bolt in the middle of the adjustment pulley with the 1/2-inch drive ratchet and a socket. Turn the lock bolt counterclockwise to loosen.
Locate the adjustment bolt on the side of the adjustment pulley. Turn the adjustment bolt clockwise to tighten the belt with the ratchet and a socket. Once the belt is tight, check the tension on the belt.
Push inward on the belt. If the belt pushes in more than a half-inch, then the belt has too much slack in it. Continue to tighten the belt until there is no more than one half-inch of slack in the belt.
Crank the engine and let it run for about 20 seconds. Turn the engine off and recheck the tension on the belt with your hand. Tighten the locking bolt with the ratchet and socket. Close the hood.