Air Conditioning

I have a 1995 Infiniti G20, with 133,000 miles. Car runs good, however I seem to have a problem with the A/C. When you depress the A/C button, the light no longer illuminates and I can't hear the cranking sound of the compressor. The air blows fine, but only warm. Before I take it to a mechanic any advise going in on probable causes would be greatly appreciated. Recently I had the passive alarm by passed because it kept going off, would that in any way be a cause?