Battery light '06 Denali

[Mobilehomie]

My battery light came on this morning on my '06 Yukon XL Denali. I put an Optima Red Top in about three years ago and have had no trouble with this vehicle. The volt meter on the dash reads 14v while driving and I double checked with a volt meter while running at the battery. When off the volts drop to ~ 12v~13v, this is on an analog meter, not my digital...What could be causing the dash light to come on? Should I simply disconnect the battery to re-set?

[Mobilehomie]

I got home last night and put the digital voltmeter on the battery, it read 12.7v with the engine off for about half an hour. I put the smart charger on and it said 97% charged and only took 15 min to get fully charged. Battery light still on while running. I unhooked the negative cable at the battery (was not real tight) and reconnected in 10 min, no light on dash, no issues driving the treacherous 2.25 mile commute to work either.

[95 S_Trucker]

With the engine running, what does your meter say the voltage is? If its above 13.5, there is a problem with the small brown wire at the alternator, a faulty cluster, or an internal circuit in the alternator. Most likely the problem is in the alternator.

[Mobilehomie]

Thanks for the reply 95 S Trucker! As I stated the negitive cable was loose at the battery and after a disconnect the dash light went out. I made a trip to Tahoe (3 hr 20 min one way) this weekend and she preformed flawlessly. I have seen lots of stories about faulty electronics on these things. I just hope that this desert environment I live in keeps those gremlins at bay.