1989 Nissan /Pathfinder.v6 4x4.
when accelarating needle goes close to 18volts and head lights get brighter than usual.

That is a problem and will cause a lot of damage. It's a bad voltage regulator which is built into the alternator so you'll have to replace the whole alternator.

Test your battery first to make sure that is good before putting a new alternator in it.




78 Corvette Pace Car For Sale-18k mi orig-Florida

Thank you very much. You have made my day.You are BLESSED!

He sure is greengrass20! Don't allow the high voltage. It will blow bulbs all over the place and be a real pill and other things possible!

T
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Tom Greenleaf - MetroWest, Boston

Thank you.

GG - expect higher than 12 - like 13.8 to 14.5 or so while running - no more!

T
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Tom Greenleaf - MetroWest, Boston