Clifton b., ase master auto tech replied 1 year ago. The blower would then be under high back pressure. What Is The Average Blower Motor Replacement Cost Due to a slow leak in your system over a period of years, the pressure of the refrigerant gradually decreases. Ac blower stops working after a while . As the relay is the switch that supplies current to the blower motor, if it fails internally, then power will be cut off from the blower motor circuit, causing the motor to no longer function or blow any air from the vents. If it is running (and the ac filter is clean) you likely have a problem with the blower fan. A vented gas cap can cause this. If your engine is overheating could be the problem of the ac not working , check the temperature sending unit located by thermostat housing , if it is bad will not let the radiator fan come on when ac is on and will cause your high side pressure ac line to get to hot causing the high side switch to disable the fan , also check the...