I have no heat.i get a 155 dtc code.do I need new control unit? frozen,seattle

Newer cars and cars with climate controls don't have a traditional heater valve that is operated by a cable to control coolant flow from the engine through the heater core. Your car has electrical heater controls and motors that operate the blend doors. I was just reading an article in a trade magazine this evening for a cheap alternative/repair kit for the blend door/actuators I just briefly looked at the companies website, http://www.heatertreater.net/ You would first need to diagnose what exactly is wrong using a wiring diagram, component locator ect...There is a company that independent auto repair shops get their information from, this same information is available inexpensively for people that work on their own cars.. The information is year make and model specific, covering repair procedures, torque specifications, fluid capacities and specifications, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate http://bit.ly/AllData_Repair_Manuals_Online