When your Ford Focus car battery goes dead and you get a jump start, but it just goes dead again, that's a good sign that your alternator is broken. The alternator charges the battery, which gets the spark to the spark plugs and keeps electrical components working in the Ford Focus. The "Volts" warning light will light up on the dash of the Ford Focus when the computer can tell the alternator is failing.
Park your Ford Focus and remove the keys from the ignition. Allow the car to cool for several hours as the alternator gets hot while spinning, or you may burn your hand while removing it.
Pop the bonnet on your Ford Focus. Locate the alternator on the back left side of the engine under the bonnet.
Locate the spring tension pulley just in front of and below the alternator. Put the proper-sized socket wrench on the centre bolt of the tension pulley and push down. Slip the belt off the alternator pulley.
Unscrew the black cable connected to the negative battery post. Unscrew the other end of the black cable from the alternator with the proper sized socket wrench.
Unscrew the red cable connected to the alternator with the proper sized socket wrench.
Squeeze the sensor tab cable end on the alternator and pull it off.
Unscrew the two bolts holding the alternator to the engine bracket with the proper sized socket wrench.