You need to find and fix what broke. The first places to start would be coolant level, engine temperature, and dash heater controls.
It may need a heater core.
yes
the thermostat used to control the heater and after we select the four pole switch to some number the thermostat start connect the power to the heater at the same time the heater start to heat and when we select the switch to zero position the heater not work
yes if it stuck open.
Yes.
== ==
The heater core is probley stoped up. You can try this and it might work. Just switch the hose's on the heater core and then go drive it and see if you get heat. Just be sure engine is COLD before you switch the hose's. If that don't fix your heat, Then PLEASE ask your question again. When you get back from driving it let it cool back off and then put the hose's back where they were and drive it again.
They work about as well as a space heater.
When my heater didn't work i had to replace my thermostat.
Not a whole of symptoms to work with here...The most common cause of "... heater not working..." is a failed temperature blend door actuator motor.See "Related Questions" below for more
Can't get my heater to work on my 156
Make sure that you typed the code in correctly. The code will only work one time, so if you or someone else has already used the code, it will not work again.