check my alternator?

You can check your voltage by simply putting voltmeter leads on the battery posts while the car is running.. should come out about 14v or so

Well what I like to do is take a DMM (digital, multi-meter) and connect the + lead to the output lug of the alternator (this is the connection with the nut) and the - lead to the negative terminal on the battery. From there I do 3 tests.

 

1. Voltage check at idle, It should be between 12.5 and 14.5 volts.

 

2. Voltage check at 3000rpm, it should be between 13.5 and 14.5. I maybe below 13.5 but it should be higher then the reading you get at idle. If it's above 14.5 then you probably have a bad regulator.

 

3. AC voltage test, sometimes the diodes get week and leak AC if you get about 1vAC it will cause problems and may damage a digital dash.

Or, you can take it into a napa or shucks or some place like that and they will do it for free. If you dont want to take it out, just drive your car to a Les schwab tire store, or some other place that does a full charging system test.