The Cadillac DeVille requires a large supply of current to run the electrical components of the car, and the alternator is the part which keeps the power flowing and the battery charged. Every time the engine is running, the alternator works like a generator to keep the battery full, and should the alternator fail or wear out over time, you will need to replace it in order to keep your Cadillac DeVille on the road and in working order.
Shut off the vehicle and park it on a flat working space. Set the parking brake and open the hood of the Cadillac. Use a wrench to remove the negative battery cable and set it to the side so you do not get shocked while working on the alternator. Locate the serpentine drive belt configuration diagram on the hood of your vehicle or on the radiator shroud and use this as a reference to loosen the serpentine belt prior to removing it from the alternator pulley.
Slot a socket onto the end of the bolt that sticks out of the tensioner pulley. Attach the ratchet and apply pressure in the direction indicated on the serpentine belt diagram chart. Remove the serpentine belt from the tensioner pulley and let the pulley slide back into place slowly. Take the loosened belt and remove it from the pulley on the alternator.
Unbolt the mounting bracket bolts for the alternator with sockets and/or wrenches. Remove the engine splash shield and radiator support access panel if you think it would make removal of the alternator easier (optional step). Remove all wiring to the alternator from other parts of the vehicle and pull the alternator out of the engine.
Reverse the process to install a new alternator. Remove the new alternator from its box and place it in the engine. Rewire the alternator and connect all appropriate connections. Mount the alternator in place and tighten the mounting bolts. Replace the serpentine belt over the alternator pulley and then repeat the process for releasing the tension on the tensioner pulley before sliding the belt into place. Replace the battery lead, remove all of your tools, close the engine and start the Cadillac.
