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Old 12-20-2017, 08:24 AM
mikeinFL mikeinFL is offline
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2003 Pathfinder
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Originally Posted by bennyb53 View Post

I suspect your issue is the alternator so you can do the load test. With a volt meter or digital multi meter take a battery voltage reading before starting the car. Start engine and after reaching normal operating temperature turn on your headlights, turn signals radio, fog lights if equipped, a/c or heater and fan on high. Then take battery voltage reading and you should get 14.5 to 14.7 volts. If you get less than 14V you need to replace your alternator.
I did the test with lights and ac full on. At 2000 RPM. Volts= 14.51 steady.

So charging looks ok? Why does it charge the batter to 12.88? And why does battery drop back to 12.6 range overnight?

I'm going to try and check the alternator diodes via this method I found. Is a valid diode test?:

" Touch the big post on the alternator (the positive terminal post on the alternator) with the red lead of the multimeter, and touch the other lead on the alternator case. With the multimeter set to measure resistance, it should measure more than 550 ohms if the alternator diode is any good. Make sure when you do it that the battery is disconnected to prevent any electrical shorts or shocks."
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