I have a nissan altima 2007 with 390k miles
Lately ive been having the problem that the battery and brake light comes on start up (which i know theres a problem with the charging system) and it stays on for 4-5 minutes and then it goes away. I checked the alternator’s voltage while the light is on and obviously there’s no output from the alternator but after 5 minutes or so the light disappears and the alternator’s voltage is at 14.2x .
i turn on the lights, ac, radio and the voltage only drops to 13.9x. I drive 4-5hours at night and the light doesnt come back until the next day when I started it again. .I tested the battery and is good state and its always charged to 100%. I cleaned the terminals as well.
checked the alternator’s voltage while the light is on and obviously there’s no output from the alternator but after 5 minutes or so the light disappears and the alternator’s voltage is at 14.2x .
Your alternator is starting to fail. It's supposed to always be above the voltage level of the battery, or at the battery's voltage level if the battery is fully charged.
I tested the battery and is good state
tested how?
