Check that the switch that moves from cool to hot (Is like a sliding switch on a 1990 Corolla I think) is actually opening the vent that controls flow of hot air
heat and a heavy hammer the larger the better
Check the heat shield on the catalytic converter
try changing out the heater core or the therma stat may be bad
The heater isn't an extra unit, it is simply pulling heat from the engine and blowing it into the cab. If the engine is not hot the heat will seem like it is not working. If the heat is not working after the engine has warmed up, you may have a fan that doesn't work, or a clogged vent.
Sorry bad news Your heater core has a leak
You may be low on coolant. Check the reservoir and the radiator, if it is empty check for leaks in the system. If it is full you may have a stuck open thermostat causing no heat.
it's in the down pipe coming from your exhaust manifold. you will have to remove the heat shield from the exhaust manifold to access it
I have the same problem I am ready to jack the chrysler up and install a Toyota underneath it
Heat is coming from the engine.
? Thermostat ?, do you have good heat, may make the computer ( ecm ) assume your on cold start up.
There is a 'lock' button on the drivers door. By the up/down switches. The driver is in control of the vehicle and I think it's right that the driver have that control. I think the driver should have a lock on the climate, heat & a/c also
This happens on new cars as well as older models, when the car warms up the idle should drop. When its cold the fluids in the motor get thick so it works alittle harder until it thins out with the heat