I have a 1999 Sebring 2 dr pilar coupe and the a/c, blower does not come on when I turn on the switch.

Sounds to me like your refrigirant is out, the system has to have the right ammount of freon to switch on, should be a easy fix at your local carshop or the service station (Im not from the States , but ive heard some service stations have do it your self fill up stations where you can fill it your self). Read your manual for the right charge in grams or ounces). Had the same issue in the beginning of the summer, even though the system is a closed system, there will always be some leaks of freon on the shaft sealer on your freon pump (Cant be avoided).hope this helps.

Could also be the your relay switch. Try these 2 things.

The blower motor has nothing to do with the amount of refrigerant. Is it the blower motor itself that is inop? Does it work on heat? Does it work on any speed at all? The resistor pack that controls the speed of the motor is a frequent culprit of blower motor problems. If the motor itself works on high but no other speeds, this resistor pack is most likely the cause. If the blower does not work on any speed, check the fuse.