The alternator in the Chevrolet Tahoe plays a big role in keeping this truck running smoothly. The 2003 Tahoe needs all the battery power it can get to run all the accessories with which it is equipped. The alternator serves two unique functions under the hood. The alternator converts the energy from the battery to a current the truck can use to power its accessories. It also keeps the battery charged during operation, which also ensures that the battery has a full charge every time you go to start the vehicle.
Open the hood to access the engine compartment. Disconnect the negative and positive cables from the battery.
Find the tensioner pulley, which is located by the water pump. The tensioner pulley keeps the belt tight while the engine is running.
Push the tensioner pulley down with a socket wrench. The pulley will have a square notch in the middle that can fit the head of a 3/8-inch socket wrench. This will loosen the belt enough to slide the belt off the alternator pulley.
Slide the belt off the alternator pulley. Place the belt to the side.
Unclip the wiring harness from the back of the alternator. Pull the release tab on the connector up and slide the connector out of the back of the alternator.
Disconnect the ground wire off the back of the alternator by unbolting the small nut on the stud with a socket wrench. Pull the wire off the stud.
Unscrew the two bolts holding the alternator in place with the socket wrench. Pull the old alternator off the mounting brackets.
Mount the new alternator to the brackets. Tighten the two bolts with a socket wrench to secure the alternator in place.
Attach the negative wire to the mounting stud by unscrewing the nut and pushing the wire eyelet on to the stud. Tighten the nut down with the socket wrench.
Push the wiring harness in to the back of the alternator. The connector will click in place.
Push the tensioner pulley down with the socket wrench. Slide the belt over the new alternator pulley once you have plenty of slack. Release the tensioner pulley and remove the socket wrench once the belt is installed on the pulley.
Connect the battery cables to the battery posts. Tighten the cables with a 7/16-inch wrench.
Start the truck to allow the alternator to charge the battery. Let the truck run for at least 15 minutes. Turn the truck off and allow it to sit for an hour. Start the truck again to ensure the battery is holding the charge.
