Auto Air Conditioning & Heater Repair: 2001 silverado heater problem, chevy silverado, air temp

Question
my 2001 chevy silverado will not blow hot air. temp. is at 200 but it only blows luke warm or cold air. I filled the truck with coolant and it did not make a difference.

Answer
Are both hoses hot going in/out to the matrix on the bulkhead. If one is hot and the other cold you have a blockage in the matrix or if you have a valve in the line, it may not be opening properly.
Is your thermostat working properly. You should have hot water hoses either side of it.

If all is good under the bonnet then the problem is in the cabin, we are a uk company so have no specialist knowledge of your vehicle and would therefore recommend taking it to the dealer to have it plugged in to the diagnostic machine.

If you can see or hear the flaps opening and closing it would be fair to assume these are working
when you ask for the airflow to move from screen to floor
If you can't hear any movement then you may have a sticking flap that will not open to allow the heat through

Hope this helps