Ford Explorer 1999 limited edition

My truck has a climate control, it works ok, but only blowing cold air, the
blend door actuator it´s ok, and when I turn the key I ear a funny click   3 or 4
times, also the temp indicator is mostly showing a cold engine, there was a
leak on the termostat housing, but I fixed it, I don´t know where is this click
coming from, bt I´m sure That is not the actuator because I opened and the
gears and the motor are ok, so I´m running out of ideas, if somebody can tell
what else to check