My old thermostat a basic Honeywell, a went blank (no temperature etc..) I went to Lowes and bought a Honeywell rth230 B to replace the old one. However after installing the new one I still don’t have AC nor does my fan come on in the “on” mode. I connected the wires, white to white etcc.. and light red to C and dark red to R. Is the problem with installation or is the AC bad? Thank you