Alternator?

Last night and today, when I tax the battery really hard on my 1992 Buick Park Avenue (run headlights, radio, front and rear defroster, put brakes on which causes brakelights to go on, put turn signal on all at the same time- besides the radio, had to due to winter weather) my red "battery" light goes on. Once I stop any of these things (release the brakes, make the turn, etc) the light goes off. The light only goes on when I have all of these things happening at once. I purchased a brand new 5-year battery earlier this year, so it shouldn't be the battery. I'm thinking I need a new alternator- am I correct?

no not really your loading the system.you could go & check out the system to see what the out put is.(13.2 -14.5)but if your doing this at an ilde(loading system)u may find its ok.

Even with all the load put on at one time, it isn't normal for the battery light to come on at all. I would bet dollars to donuts the alternator is bad. Especially if you haven't changed it in a long time and the battery is good. You can pull the neg cable off the battery when it is running and if it dies, then the alt is bad. If not, then look elsewhere. This is an old school method, but rather easy to tell if the alt is charging or not.

You can pull the neg cable off the battery when it is running and if it dies, then the alt is bad. Since these CS-series alternator regulators are now essentially an electronic computer chip, be sure to disconnect the battery before servicing and NEVER remove the battery cable when the engine is running. This is no longer a viable way to test alternator output! If you do this, you may destroy the regulator’s computer chip and the PCM. You must really begin to think of these alternators as computers, and treat them with the respect that you might a laptop computer. A volt meter can be used at the battery leads for testing alternator output voltage. Unloaded, it should be around 14.2 to 14.8v. Under heavy load. it should still maintain 12.6v.