Toyota Repair: Car heater does not heat during cold weather, toyota corolla, heater valve

Question
Car heater is not heating, just gives luke warm air. Thanks

P.S. 1997 Toyota Corolla 1.6 L 4 door with Air conditioning. Mileage 182,000km


Answer
Some things that need to be checked:
Does the temperature gauge on the dash come up to operating temp? There may be a problem with the thermostat, if it stays open the engine will not heat up in cold wheather and the heater will be inefficient.
Check to see that the heater valve control cable is connected and that it moves the valve lever when moving the control from cold to hot.
Check the blend door control cable under the glove compartment, you may have to remove the glove compartment, make sure the door moves open and closed when moving the heater control, this door moves when switching between heat and A/C.
If all the controls are working properly, remove the heater valve and make sure it opens and closes, if so the last thing that may cause this problem  is a clogged heater core.