AC indicator/pushbutton blinks

'96 Toyota Avalon. AC pushbutton/light blinks every so often. When this happens I can tell the AC isn't quite working up to par, and fan still runs. When I turn it off, then on again, it stops blinking and works fine. Very intermittent.

Is this a typical indicator that the refrigerant is low/bad or might it be something else like the switch or something electrical?

Thanks.

I think the Avalon forum is the place for this thread.