Heater not Working *2007 Prius*

Whenever I put my heat on it just blows out cold air. It would get hot when I would accelerate and then cold when I stopped accelerating before, but now it doesn't even do that. It stays cold no matter what. I recently had the check engine light come on and when we read the diagnostics it came up as the Coolant Control Valve. So I replaced the coolant control valve with a new one, and the check engine light isn't on anymore, but it still only blows out cold air not matter any setting I try on the system. Please let me know if you have any idea what this could be, thanks!