I'm buying a new alternator for my 2000 Ford Taurus 3.0 l v6. The battery light comes on and when I start it it'll run until I take off the negative wire, so do I buy a alternator or a battery
Have your local auto parts store load test the battery to see if it's fine, why replace it if you don't have to.
First don't do the battery cable test on the alternator!! The alternator must be dead if the car still runs or you'd have fried the computer by doing that test!! When replacing the alternator replace the large 2 or 3 wire plug that plugs into the alternator. They're notorious for burning out. HTH. -Jim