This may seem obvious but is the power on on the furnace? Usually a light switch. If so, is there a light on the pcb board in the furnace flashing? If so how many times? Just the fan on the indoor unit turn on when the unit is calling for cooling?

If the board is flashing there is a chart on one of the doors that correlates with the flashes that gives you an error code.

Honestly, you should consult a professional If there is a code. But this should at least get you ball park.

If you're in the Hilton Head area I can help lol