What does the green light on the A/C button mean?

Most people believe that the green light means the air conditioner compressor stays on all the time. This is not true.

From a post by Lorrin Barth:

"When the green light is on the air conditioner cycles off when the oulet temperature of the evaporator drops to 37 degrees and cycles on when it rises to 39 degrees. In other words, cold air all of the time. Of course, as in really hot weather, the evaporator temperature may take a long time to drop to 37 degress, and this is going to depend on the condition of the system too, making you think it never cycles.

So, as you can now see, the compressor cycles in either mode. To see exactly how this all works check out the graph at the bottom of page 24-4 of the "Technical Information Manual". "