How to Replace a Nissan Alternator

by Eli Laurens

Nissan automobiles use an alternating generator to produce power for the battery, engine and accessories. This alternator can wear out and require replacement. The only major difference between different models is the use of a single- or serpentine-belt drive system. Replacement of the alternator can take the average backyard mechanic between twenty and forty minutes to complete.


Disconnect the alternator and battery from the wiring harness by turning the positive terminal nuts counterclockwise. Start with the battery terminal, then disconnect the alternator second. Place the terminals away from the battery.


Remove the serpentine belt from the alternator pulley wheel (for single-belt systems, proceed to step 3) by pressing firmly on the tension pulley arm, then sliding the belt out from underneath the idle pulley. Release the tension pulley arm and the belt will loosen around the alternator pulley wheel and can be removed.


Remove a single belt from the alternator by loosening the adjustment bolt (and the other mount bolts) so that the alternator will shift its position, slackening the belt for removal from the pulley wheel.


Remove the mount nuts by holding the bolt heads with a wrench and turning the nuts counterclockwise. Slide the bolts from the mount and remove the alternator. Replace the alternator with a new unit by positioning it in the mount arms and sliding the bolts back through. Secure the mount bolts with the nuts, but for the single belt system you should only finger-tighten them. For serpentine systems, lock all nuts tightly.


Replace the belt around the alternator pulley wheel. Either press the tension arm and slide the belt back under the idle pulley wheel, or lever the alternator with enough force to give the belt tension. Secure the adjustment bolt when the belt has about a half-inch of play. Releasing the tension arm will automatically adjust the belt, and it will tighten around the pulleys.


Reconnect the electrical system by turning the alternator positive terminal nut clockwise, then the battery terminal nut second.


  • check Have the old alternator checked at a parts store to ensure it is actually at fault.


  • close Use extreme caution when working with a vehicle's electrical system.

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About the Author

Eli Laurens is a ninth-grade physics teacher as well as a computer programmer and writer. He studied electrical engineering and architecture at Southern Polytechnic University in Marietta, Ga., and now lives in Colorado.

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