Q: The heat, ac, and defrost isn't blowing out the vents

Blower speed in your application is controlled by a replaceable resistor block in the blower motor circuit. If various fan speeds have become unusable, and now you are left with nothing, a possibility is all positions in this resistor block have failed. If so, the service to request is replacement of the blower motor resistor block. Prior to replacement, of course, the mechanic will check the resistor block for continuity (i.e., specified resistance in ohms) at each position just to be sure that failure of the block is the cause. There are other possibilities, of course, including faults with the blower switch and the plug connection on the back of the switch, as well as the rest of the circuit not to mention the blower motor itself. If equipped with a relay in the circuit, that is easy to test and if the relay works consistently as commanded, you can assume there is no fault there. If you want these diagnostic steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a non functioning cabin heater diagnostic and the responding mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic.