Alternator Voltage High

nissan
sentra

#1

98 Nissan Sentra with 240K miles on it, very well maintained. The alternator is only three years old, but is now putting out over 16 volts, agreeably bad.

Is there anyrepair/replacement possible of the internal regulator?


#2

It can be done but it is usually better to just replace the alternator with a remanufactured unit I feel.


#3

Be sure you are getting the correct voltage reading, measured at the battery, with a known good meter. Do NOT start buying parts on the strength of a dashboard meter reading…


#4

I looked at the manual for a 98 maxima alternator, which I assume is similar to yours. The regulator replacemet doesn’t look to be too bad of a job.

I’m not sure from the drawing if the front pulley is held on with a nut or pressed on to the shaft. If it is pressed on, you need special equipment to remove and install it.


#5

Be sure to check the connection between the main output lead of the alternator and the battery positive cable. A disruption in this circuit can cause an artificically high voltage reading.

Many vehicles use a fusible link in that circuit so a blown link is something to consider.
If there is a problem in the alternator/regulator then the entire unit should be replaced.