I have a 05 GTP Comp G with the 3800 series III supercharged engine heres a list of things i changed on the car

1.New Radiator
2.New Thermostat
3.New Hoses
4.New Clamps
5.New DexCool Recommended Antifreeze/Coolant
6.New Overflow/Back Up Container for Coolant
For some reason or another the heater isnt working,both the radiator & coolant container are full with DexCool Antifreeze Coolant so i dont understand why the heater isnt getting hot.I noticed this last night while on my way to work,i always let all my cars run until they reach normal and safe operating temps before i pull off,no matter the weather,i live at least 20 miles from my job,but after almost 13 or so miles no heat just cold air blowing out the vents,both fans are working car is running at normal operating temp,but i cant figure out why the heat isnt working,the heater core nor the water pump is leaking so im just wondering what could it be?????