I just bought a 2009 Murano a few weeks ago and suspect that I have alternator problems.
When my vehicle first starts up, the measured DC voltage is around 14.2VDC for about 10-seconds then it drops to around 13.2-13.4VDC. This remains in the same range even with the lights, AC, fan and radio is on. From what I have read, this is somewhat normal.
My problem is that there is a warning dash light indicator the shows BOTH the "Battery" and "Brake" lit and is intermittent. When both these lights are lit, this indicates low voltage from the alternator from my investigations and searches on the internet. I wired up a Voltmeter and monitored the DC voltage via the 12V cigarette lighter socket. When both these lights were lit, the voltage dropped to around 11.8VDC and when they were not lit, it jumped back to the 13.2-13.4VDC range.
I removed both the POSITIVE and NEGATIVE terminals from the battery (in addition to an overnight charge) and cleaned all and any corrosion that I observed. The following day, I noticed that the indicator lights for the alternator did not come back on over a 100-mile drive. It did once (for about 2-seconds) appear and then stopped.
The Murano sat for 2 days then would not start even though all the dash indicator lights were lit and everything else worked (radio, fan...). I checked the battery voltage and it was at 12.8VDC, even when trying to start the vehicle, there was no voltage drop or current draw noticed. It would not even start with a jump from another vehicle. I suspected a relay or possible connection problem.
Later in the day, I attempted to wiggle the battery cable harness going down into the maze of darkness. I also pushed the gear shift totally forward to confirm it wasn't a safety switch issue. The Murano started immediately as if there were never a problem! But now, the alternator indicator light issue started again, but not as frequently. Today I had the vehicle idle for over 2-hours and it never came on except for 2-seconds and stopped. The vehicle starts fine and has never had the "no start/no draw" problem again, it was just that one time previously stated.
I was going to have a local mechanic change out the alternator but he said that he didn't want to do anything to it unless the problem was happening...and the charging issue is intermittent.
Is it possible that my alternator is good but has a bad grounding strap somewhere that will cause the "battery and brake" light to come on intermittently? If anyone on this forum can give any suggestions, I would appreciate it!