There is a belt tightener on the alternator which must be loosened to take the belt off. After the belt is loose, remove the bottom mounting bolt and the alternator is off. you will also need to remove the wiring.
Alternator belt is probably loose and slipping. If you can turn the alternator by hand and the belt slips its too loose. Retension alternator belt
Corroded or loose battery connections, loose alternator drive belt, defective alternator, or dead cell in the battery.
alternator, or a wire to alternator loose
You will need to loosen the alternator belt with the tensioner pulley. When the tensioner pulley is loose the alternator belt will become loose. Put the new alternator belt on and tighten the tensioner pulley.
Can be loose or corroded battery connections, loose drive belt, or the alternator is failing.
Not knowing the year, make, model and engine I suspect you have more parts to remove.
I assume it is V-belt drive, is the top of the alternator sliding in the slotted bracket? (check if you need a washer or two, or stripped threads) but sounds more like a cheap belt that is stretching.
Have the charging system checked. Possibly loose or corroded wiring, a loose alternator belt, or a bad alternator.
Make sure both the top and bottom bolts are tight, if the bottom is loose the alternator can "wiggle". Also I have noticed that the top bolt may sink into the slot provided for alternator belt adjustment. I put a slightly larger diameter thick washer on the top bolt and it cured "the agony of the screech"!
loose rocker arm[s]
Loosen the alternator tensioner bolt. The alternator belt will become loose. Remove the alternator belt. Put the new alternator belt on and reverse the process.
Loosen the tensioner bolt on your 1997 Kia alternator. Move the alternator to the left. The alternator belt will become loose and can be replaced.
By looking for any loose threads
It is defective or the alternator belt is loose.
This is moderately difficult. Disconnect the battery, use a 15mm box wrench to pull tensioner and slip belt off, there is a top bolt and a bottom bolt on alternator to take loose, also 15mm. once it it loose you can unplug the one wire, and take the nut off the battery terminal, wiggle the alternator around and take it out, install in reverse order. AJ
The light is on because the alternator is not putting out the required voltage. Either the belt is broken, loose, or the alternator is defective.
Jack the car up in the rear and pull off the passenger side rear wheel. you will be able to see the slider that the alternator is mounted on. remove that bolt and clawl under the car to remove the top bolt from the alternator. the reason for this is that the alternator has to come out of the bottom of the car. you will want to be under the car to catch the alternator when it come loose. repeat steps in reverse to put alternator back on. use a bar to put tention on the alternator to get the proper tention on the belt.
I have a 1989 celebrity and it was quiet easy to change the alternator, done it a dozen times. There should be 1 main bolt in the back on the bottom of the alternator,(side toward cab). This bolt goes all the way through the mount. Then on the front side there should be a bolt that screws into a mount. Disconnet the main battery cable and unplug the wires on the bottom and there it should be loose.
Just did it, Need to partially remove the driveshaft on the drivers side. It only comes out the bottom (barely). Worth getting a shop manual from the library. Need to remove the bottom of the strut assembly and the bottom ball joint as well to get the axel loose.
To reach the alternator on a 2000 Honda Civic loosen the adjustment bracket. Pull the loose belt off then loosen the bolts for the alternator. Replace the alternator.
Loosen the tensioner pulley. The alternator belt will come loose. Remove the alternator belt. Put the new alternator belt on and tighten the tensioner pulley.
Loosen the tensioner pulley. The alternator belt will become loose. Take off the belt. Remove the wiring harness from the alternator. Remove the retaining bolts from the alternator. Remove the alternator. Reverse the process to install the new alternator.