How to Replace the Alternator on a 1999 Cadillac Seville

The alternator is an essential part of your vehicle's ignition system. By using the energy produced by your engine while it's running, the alternator can constantly recharge the 12-volt battery and supply electric current to other necessary vehicle components. A malfunctioning alternator can reduce the life of the battery or drain the battery completely and leave you stranded. You can remove and replace the alternator unit of your 1999 Cadillac Seville yourself with a few basic hand tools.

Things You'll Need

• Wrench set
• Safety glasses
• Vise

Instructions

1. Open the hood of your 1999 Seville. Locate the alternator in the engine compartment by following the serpentine drive belt to the alternator, which is near the top of the engine.

2. Put on safety glasses. Disconnect the negative battery cable from the battery with a wrench.

3. Locate the belt tensioner pulley, which is directly below the alternator. Pull the belt tensioner pulley down with a wrench to create slack in the serpentine drive belt. Slide the belt off the pulley while the slack exists.

4. Lift the tab on the electrical connector on the alternator. Unplug the wiring harness.

5. Remove the bolt securing the negative battery lead to the alternator with a wrench. Disconnect the battery lead.

6. Remove the upper and lower mounting bolts securing the alternator to the motor using a wrench. Remove the alternator. Tap the alternator with a rubber mallet to loosen it if you have trouble removing it from the motor mount.

7. Tighten a vise around the alternator pulley and hold the alternator firmly with one hand. Remove the pulley bolt with a wrench, using the other hand. Remove the alternator pulley.

8. Replace the existing alternator with a new or rebuilt alternator by following the removal steps in reverse.

Tips & Warnings

• Alternators often can be rebuilt, which may be cheaper than purchasing a new one. Consult mechanics who specialize in alternator repair to determine whether rebuilding the alternator is an alternative for you.

• Test your alternator before having it rebuilt or purchasing a new one. Auto parts stores often test alternators for no charge.

• Consider having an assistant route the serpentine drive belt back into place while you apply pressure on the belt tensioner.

References

• "Cadillac Haynes Repair Manual for DeVille (1994 thru 2005) and Seville (1992 thru 2004)"; John Haynes 2005
• Mobile 1: Replacing an Alternator
• Nations Auto Electric: How Does an Alternator Work