My AC works fine but the Heat blows cold air....until one day it starts making a clicking sound and then it starts blowing extremely hot air (the clicking sound stops once the heat is working). I try to put it on the heat setting about mid Sept so by the time the weather gets cold it's usually started working.

The problem with the 2003 and older models, the actuator is located under/behind the dash and not in the engine. The labor to replace the actual actuator is about 1.1 hour and the part is $100, maybe more, no listing in the manual but that is a reasonable number. But you have to remove the entire dash which takes 10 hours, more or less. that equals $$$$!!!

This car sucks! Clearcoat delaminated on hood, roof, trunk. Heater valve actuator motor stopped working which stopped hot coolant from getting to heater core under dash. Thank God for on line blogs which showed exactly where and how to replace it. (Not too difficult for a backyard mechanic. $150 part at dealer). Horn stopped working right before inspection time. Horn switch is part of airbag module, approximately $300 from dealer only. Rigged up horn switch on dash to pass inspection. Front window actuators both broke within 3 months of each other, had to get used one ($80) and take doors apart to replace. Then to top off my Mitsubishi experience the transmission blew. $1000 These cars are cheap crap. I would only own another one with full warrenty.