If I may suggest, dont meddle with your heater. If you dont like a warm temp just decrease the temp to 22. Manually set the air flow (mode button) to upper part only.
The heater is usefull to warm up the leg during cold wheather like in genting. You can set it warm at the foot and cold on the upper part. Likewise your passenger can set up his or her own temp if desires. It is a dual mode. If you adjust temp from the driver side it will automatically adjust all unless you press the dual mode button.
The heater is also part of the whole a/c system and it is needed to dries up the evaporator to prolong its lifespan. You have one rather advance system in your car