My fans do not come on in my 91 max even after idleing for 30 min. and the temp is above half way. My question is, that they do come on as soon as I switch the a/c on....so, even though i will address the problem and fix it so the fans come on when they're supposed to, is there any harm in damaging either the heating or air conditioning systems by switching on the a/c if i'm sitting in traffic for awhile, i.e. use the a/c switch as an on/off switch for my cooling fans?

 

That should work just fine until you fix the problem.
It's probably a coolant temp switch, sensor or relay thats gone bad.
When it's below freezing your A/C compressor will not turn on, neither will the fans. Just keep that in mind, but when it's that cold outside the cooling fans probably wount need to come on. Keep you eye on the temp gauge, don't let your engine overheat.