Compressor Works Intermintenty

by Robert
(Fl)

i have a 3.5 ton American standard about 13 years old, never had any problem with.until now, the model is ATN042C100A0.The compressor works sometimes. it will cool the house down pretty good, then when it starts up again, everything works except the compressor,it will run and cool the house down on fan only and stops then starts up again,but the compressor wont come on..just once awhile, it will kick in..i have a new battery in the stat, have 24 volt running,, i would appreciate any help on this one.thanks in advance for this help..