A/C-Heater system

[Will308]

I'm having trouble with my system. I tried to turn on the a/c to clear the fog on the inside of the widshield and the little green switch lights won't come on for either the a/c ( snowflake symbol) or the recirculator ( circular arrows).
I checked the fuses and they're O.K.
I've been noticing an oder coming from the vents but it doesn't smell like anitfreeze. I attempted to replace the microfilter to solve that problem and discovered that my car doesn't have one.While I was poking around ,I noticed that there was a build-up of a greenish, stickey substance in the plastic cover for the evaporator. Does anyone know what this might be? It doesn't seem to be antifreeze.
Thanks for your help1
Will

[ejhiggins]

Your a/c system may be low on refrigerant that's probably why the compressor is not working, most automotive refrigerants have a green dye so that leaks are easy to find, i'm guessing that's the green build up on the evap cover, hook up a refrigeration gauge to check if you have any refrigerant in there.

[Will308]

Thanks, I thought there might be a sort of safety device to protect the compressor.