Replaced a honeywell with a honeywell digital model CT877SC. 5 wires, R to R with jumper between R and Rc, Y to Y, G to G, B to B and W to W. AC will not run in AC mode but on heat setting. Only flashes snowflake on AC mode. What is wrong with this thing? Do I need another jumper somewhere?

Did you do the switch setup settings like in the manual. Here is your manual


http://customer.honeywell.com/techlit/pdf/PackedLit/69-1676.pdf

Yeah, I did all that I am wondering if I got a bad thermostat. It still is not working right.