The Plymouth Neon uses an alternator to run electrical devices in your vehicle while the engine is running. A voltage regulator ensures the voltage level remains constant and is usually part of the alternator assembly. You may need to replace the alternator if your battery continually runs down or your headlights become dimmer while the engine is running.
Determine which alternator your Plymouth Neon will need. You'll want to be sure the new alternator is compatible with your Neon's engine. A Plymouth Neon can have a 2.0 L 420A or 2.0 L A588 engine.
Disconnect the negative battery cable with a socket wrench. Loosen the alternator jam nut and adjustment nut with a socket wrench. Remove the accessory drive splash shield.
Loosen the lower alternator mounting bolt so you can remove the alternator drive belt. Push the red locking tab to release the alternator field circuit connector. Remove the positive terminal nut with a socket wrench so you can disconnect the lead from the battery. Remove both mounting bolts on the pivot bracket with a socket wrench and detach the alternator from the pivot bracket.
Install the new alternator assembly into the pivot bracket and tighten the mounting bolts with a torque wrench to 49 ft. lbs. Connect the alternator field circuit connector to the alternator and push the red locking tab to secure it. Replace the lead from the battery and tighten the alternator terminal nut with a socket wrench.
Replace the accessory drive belt and tension the drive belt to 100 lbs. for a used belt and 135 lbs. for a new belt. Torque the jam nut and adjustment nut to 40 ft. lbs. Reconnect the accessory drive splash shield and negative battery cable with a socket wrench.
