Any of the following...................
1. Low coolant level.
2. Clogged heater core.
3. A/C heater controller bad.
4. A/C heater doors not working.
5. Vacuum problems........
The blower may simply have burned out. If the blower is out then the heater probably still works.
Check the Heater blower motor, any vaccuum lines that go into the heater, and fuses under the hood. Sounds like a blower motor though.
probably the blower motor resistor
Fuse- Blower Motor- Wiring- Selector switch fail- i8f you still have heat to the heater core, if the heater core is cold, and the mottr is still hot... change the thermostat
Could have a clogged line feeding the heater core. Disconnect return hoses from the heater core and verify coolant is flowing through the core.
I hope you checked the fuse.
First you have to see if your blower motor is working or not. If it is and still you have no heat then your heater-core is blocked and needs to be replaced.
I have changed resistor a d blower motor still not working, maybe i missed a fuse or could the control switch not work?
Yes. Hot water comes from the water heater. The blower motor propels warm air around the house through the duct-work, but is not connected to the hot water heater in any way.
if the blower motor still works, somebody probably bypassed the heater core in the past.
Under the hood, on the firewall, passenger side, close to the blower motor. If the blower motor resistor is burned out, you should still have the high speed function.
The AC and heater are completely different subsystems. The heater relies on heat generated by the engine and circulated by the engine coolant (radiator fluid) while the AC uses a belt driven compressor and separate fluids. Their only normal commonalities are the blower motor (which you said works), the ducting and the control head.