How do you replace the alternator on a 1999 Pontiac Sunfire 2.2L?

Disconnect the negative cable on the battery. Loosen the tensioner for the accessory belt for the alternator and remove the belt. Remove the two long bolts that are holding the alternator in the bracket. Do not let the alternator fall and tear the wires. Support it as it comes loose so you can reach the wires. Remove the main battery wire off of the single power connection on the back of the alternator. Remove the electrical connector that is the field connection from the back of the alternator and put it out of the way.

Install the new alternator with the bottom bolt first. Rotate the alternator upward and insert the top bolt through the bracket and alternator and then tighten top and bottom bolts. Install the main power wire to the back of the alternator followed by the field wiring harness connector. Install the accessory belt and tighten. Check the battery before starting and make sure it is not to low. If it is, charge the battery before starting so as not to damage the new alternator. An alternator is not designed to run at full capability for extended periods. This will overheat the new alternator, possibly causing damage. If the car does not have a voltmeter gauge then it is a good idea to use a voltmeter and check across the battery with the car running. There should be a charge of 14.5 going into the battery.

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