2003 Chevrolet Astro "heater defroster wont work 03" Questions

...WONT BLOW OUT PANAL VENTS AC BLOWS OUT VENTS UPON START UP BUT WHEN U GET GOING DOWN THE ROAD IT SWITCHES TO THE DEFROST THEN IF YOU STOP TURN OFF THE AC THEN TURN IT BACK ON THROUGH THE PANAL VENTS ...

...defroster doesnt work. i checked the coolant first and it was full. trying to decide if it needs a flush, a new thermostat, or both. the car never overheats and theres no leaks in the floor from a ...

...heater problem that I did have along with the rear defroster/running lights and the lights going out completely while driving, if you have the a/c or heat turned on. I am now down to the fuel pump. ...