I Have a 2013 Honda accord EX and just replaced the battery. While the car was running, I took voltage readings at the battery and at the alternator and they both read 12.6 V. Does this indicate that the alternator is faulty? No warning light on dash appeared either. I checked all the belt, wiring and connections and they seem fine. Could there be a fuse issue? I read somewhere that there may be a fuse or relay that could be bad that won't tell the alternator to "turn on". Any help will be appreciated.

 

FOLLOWUP...while I was searching for a new alternator I came across an article that said that the computers on some newer vehicles will not raise alternator output to 13+ volts unless the headlights or some other system that draws a lot of electrical current is switched on first. So I turned on your headlights and retested it and the voltages read what they should be reading. Can anyone verify this?

 

The voltage will vary depending on what all is using electricity. I remember watching the volt number go up and down when the AC fan turned on and off. If you have terminal grease on the battery connections and the battery is staying charged enough to start the car after powering on and off, I wouldn't worry about the alternator. You can have them test it at a Oreily's or AutoZone, but you have to test it in the car while it's running. They can't test this model's alternator while it is removed from the car.... or so I was told at Oreily's.
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Thx lolv8s...all I know it was much easier to diagnose stuff in the "old days". I could test to see if the alternator was working by simply testing the voltage at the battery while the car was running. Not so straight forward any longer :-(

 

I had a problem where at idle at night, the lights would dim a bit until engine RPM increased. This indicated to me alternator diodes going out. Replace the alternator and problem is no more.