I NEED HEAT!!!!

Where's the heat...???
MY 2002 4runner used to have good heat and A/C . The A/C still works pretty well, but the heat is almost not there. When I turn heat on high, the driver side gets warm at best, and the passenger side is c-c-c-c-old. I know there was a relay or something under the dash that was making weird noises last year, and then it quit altogether. Thinking that it was one of the damper controls? Does this sound reasonable? I still get plenty of air blowing, its just not hot.

 

Ok..so i did a complete flush of the coolant system... as complete as i think i can get?? Disconnected heater core, and connected a flushing device...and let the water run... then i flushed the heater core as well. Still no heat.. either there is a blockage in the heater core, not allowing it to heat up, or theres a damper issue. I also took the dash apart behind the glove box... everything works well on that side. I can see the dampers working as i toggle thru the controls... now i need to see the other side...anybody out there got any tips?