Need help from the automotive hive mind.
I have a a 2005 Focus, 199,000 miles.
The battery light has been come on randomly. It doesn’t seen to be related to any other event in the car.
Things I’ve done to diagnose it.
I cleaned the battery cable connections before I started any diagnostics
I have two code reader and no codes are being thrown.
I connected a multimeter to the battery while the car was idling in the driveway. I got 13.8-14.1 volts as the car sat and ran. When the light came on no change on the meter.
I have a Scan Gauge that allows me to watch the voltage in real time. Four days and no change when the light came on. ~13.8-14.1 at idle and ~14.1-14.4 underway.
I have the Car Chip. I plugged it in drove for about 10 runs and the voltage trace was pretty flat on all runs, battery light on or off.
The only thing that is consistent is if the light is on and I rev the engine it goes out BUT they rpm when the light goes is inconsistent.
So before I take it to a shop that wants to sell me a battery AND and alternator I hoping others have seen this and can point me to a fix that won’t break teh bank.