Blowing air and lack of heat are two separate agendas. If you have air circulating, your blower is fine. The heat in most auto heaters comes from hot water being circulated from the coolant system .i.e. radiator (cool), engine block(hot), through the heater,(hot), back to the radiator,(cool).
Some where you have an interuption in this system.
check the blower motor resistor it may be burned out
that heppend to my car i had to finaly replace the heater blower so it could be the same thing
You may have a faulty switch that controls the speeds on the a/c blower fan.
Blower circuit board is shot
Your front blower motor has gone out. There is a front and a rear blower motor.
Does blower operate at all? If not it could be blower motor, fuse/fusible link, faulty switch, blower resistor pack...sorry not enough info for much more help than that (model, year, just heat not working...or a/c also?)
First find out if the blower works. To do this disconnect the hot wire from the blower and use a jumper wire from the positive of the battery and connect it to where that hot wire was. if it does not go;;; then check that the blower motor is grounded.
If you are talking about the thermostat in your engine, the two have nothing to do with eachother. If there is no air at all coming out the vents, I suggest it is your blower motor.
check the blower fuse if the fuse is good the blower motor is bad or else you have short
where is the location of ac blower relay
Something with the blower motor. It may be as simple as a bad fuse, or it may involve wiring or even the blower motor itself.
possibly blower motor some libertys had a recall call your dealer and check also could be the blower motor resistor