The alternator on the 1999 Nissan generates power for distribution throughout the automobile's electrical system. The electricity is available on demand when the car is running. Anything that you try to power, when the car is off, will draw electricity directly from the battery. When the alternator stops working, it will stop generating electricity and begin draining the battery. If you begin to notice problems with the alternator, such as the lights getting very dim, it's because of a voltage drop in the alternator. You will need to replace it.
Detach the negative cable on the battery, loosening the nut on the terminal with a wrench.
Disconnect the two electrical leads by removing the nuts with a wrench. Unplug the voltage regulator from the alternator.
Loosen the adjusting bolt on the alternator with a ratchet and socket. Pull the belt off of the alternator pulley.
Remove the alternator bolts with the socket and ratchet. Pull the alternator out of the car.
Install the alternator in the car and tighten the bolts with the ratchet and socket. Put the belt on the pulley and tighten the adjustment bolt until the belt is tight.
Plug in the alternator voltage regulator. Reconnect the two electrical leads and tighten the nuts with the wrench. Reconnect the battery and tighten the terminal nut with the wrench.
