Ernesto Aragon

Hello everyone,

About a month and a half ago I replaced the clutch and after I finished, the battery light came on while I was driving home. When I parked, I checked the alternator output with my voltmeter and got about 12.20v while the engine was running.

I replaced the alternator and I have the same problem. The battery is less than a year old. There's no check engine light on, only the battery light comes on after the engine runs for half an hour or so. I checked to make sure I reconnected all the grounds after I finished the clutch job and didn't find any problem there.

I checked the alternator harness connector voltage while the engine is running and got the following results with the alternator output at 12.20ish volts:

White/blue stripe .94v
White/red stripe 1.64v
Black/yellow stripe 0v
White/green stripe 0v


Other Info that may be helpful:

While I was replacing the clutch, there was a slight drizzle that got under the hood wet. I did have the battery disconnected during the entire job, but I wonder if when I turned the car on several hours later, even though everything looked dry, maybe there was an electrical spike in the alternator wire harness that may have shorted something out?

Also, if I turn the car on first time during the day, I will get 14.24ish volts from the alternator, but after the car warms up, the voltage unexpectedly drops to 12.20volts and then the battery light comes on. This seems to always happen.

Could the problem be with the ELD unit or a bad pin on the alternator output pin on the ECU, and if so, how would I test for these potentially problems?

Thanks in advance,


Ernesto