# Brake and Battery Warning Lights Flash Intermittently



## Eurodude (Feb 1, 2015)

The family has a 2003 Altima 3.5 SE with ~140K miles on it. For the last few months, the battery warning and brake warning lights have been briefly and intermittently flashing on the dashboard when driving. It happens intermittently and at different times of day and driving speeds and conditions, be it day or night, city streets or highway/freeway. The car has been to the shop for this issue but nothing has been found and no codes in the ECU.

Any thoughts?


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## smj999smj (Jan 1, 2006)

Brake and battery warning lamps on is a sign of a charging system malfunction, usually an alternator that isn't charging enough or a an alternator that is overcharging. Proper range should be 13.2-15.0 volts, with loads on and off and throughout the RPM range. Check your battery cable connections and make sure they are clean and tight. One thing you can try is get a voltmeter that plugs into your power socket (cigarette lighter socket). You can pick one up for around $10 at the auto section at Walmart or in auto parts stores (see image link below). Install it in your power socket and drive your vehicle. When the lights start flashing, check what the voltage reading is on the voltmeter and see if it falls within that 13.2-15.0 range. I worked on a 2002 Altima years ago that would start and run fine, but several minutes down the highway it would start bucking and dash lights would go crazy! When I checked my handy voltmeter, I found out that as I drove it, the voltage would gradually climb to 18 volts, which is way too high. The alternator's internal regulator was faulty, requiring a new alternator.


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## Eurodude (Feb 1, 2015)

smj999smj said:


> Brake and battery warning lamps on is a sign of a charging system malfunction, usually an alternator that isn't charging enough or a an alternator that is overcharging. Proper range should be 13.2-15.0 volts, with loads on and off and throughout the RPM range. Check your battery cable connections and make sure they are clean and tight. One thing you can try is get a voltmeter that plugs into your power socket (cigarette lighter socket). You can pick one up for around $10 at the auto section at Walmart or in auto parts stores (see image link below). Install it in your power socket and drive your vehicle. When the lights start flashing, check what the voltage reading is on the voltmeter and see if it falls within that 13.2-15.0 range. I worked on a 2002 Altima years ago that would start and run fine, but several minutes down the highway it would start bucking and dash lights would go crazy! When I checked my handy voltmeter, I found out that as I drove it, the voltage would gradually climb to 18 volts, which is way too high. The alternator's internal regulator was faulty, requiring a new alternator.


Thanks for the reply. The lights I mentioned are not actually on when driving. They intermittently flash every so often. But I will advise the family member to acquire a voltmeter that plugs into the cigarette lighter socket and monitor the voltage.


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