Virtually all cars have alternators, which keep batteries charged and power a car's electrical features. Replacing the alternator on a Saturn SL can be challenging, due to the location of the alternator within the SL's engine bay. A Saturn SL's alternator is located at the lower left passenger side of the engine block. In order to replace it, you'll have to jack up that corner of the Saturn or drive the front two tires up maintenance ramps to gain access. Once the front passenger side of the SL is up in the air, you will work under the car to pull out the old alternator and put in the new one.
Park the Saturn on a level work surface and apply the emergency brake. Open the front hood to expose the engine. Detach the negative wire from the battery terminal using an adjustable wrench to cut off all electric to the vehicle. Lodge the wire to the side so it won't come in contact with any exposed metal.
Locate the passenger-side front lift point on the SL, behind the front passenger wheel where you will place the maintenance jack. Loosen the SL's front passenger-side wheel's lug nuts, but don't remove them. Then jack up the Saturn slightly to get the wheel off the ground.
Remove the four lug nuts and wheel. Remove the two plastic shields located at the back of the wheel well by using a slotted screwdriver to pop off the fasteners, and expose the lower engine block and alternator.
Locate the serpentine belt tensioner to the right of the alternator and secure a 15mm box wrench to the center bolt. Pull the box wrench to the left, releasing the tension on the serpentine belt. Slide the serpentine belt off the tensioner pulley and release the box end wrench so the tensioner falls back into place.
Slide the serpentine belt off the alternator pulley, which is located at the lower left corner of the engine. Remove the bolt that secures the plastic shield to the alternator with a ratchet and 10mm socket. Slide the plastic shield out to expose the alternator mounting bolts and wire connections.
Unplug the electrical harness from the alternator. Remove the nut located on the back of the alternator and detach the positive wire that leads to the battery. Loosen and remove the two mounting bolts that secure the alternator to the engine block, using a ratchet and 13mm socket.
Manipulate the alternator to remove it from under the car. Slide in the replacement alternator and attach the positive battery wire to the back of it, securing it with the nut you removed earlier. Align the alternator mounting holes and thread in the bolts that secure the alternator to the engine block. Tighten the bolts with a ratchet equipped with a 13mm socket. Attach the electrical harness.
Replace the plastic covering that protects the alternator and secure it with the 10mm bolt. Slide the serpentine belt over the new alternator pulley. Secure the 15mm box wrench to the serpentine tensioner pulley and pull to the left. Slide the serpentine belt over the tensioner pulley. Release the wrench to apply tension to the serpentine belt.
Thoroughly inspect the serpentine belt to make sure it is correctly placed over the pulley system. Replace the plastic covers inside the wheel well and secure the wheel back onto the hub with the four lug nuts. Attach the negative wire to the battery terminal and secure it in place using an adjustable wrench.
