Is theheater blowing cold airinto the car, or is the car heater not blowing any air at all?
If the heater isn’t blowing any air, skip to the next section.
Check the coolant level.
Lifewire / Maddy Price
Turn off the vehicle and let the engine cool completely.
The coolant is housed in a translucent plastic jug in the engine compartment.
It should have level indicators that show how full or empty it is.
Adding coolant might fix the problem in the short term.
However, low coolant often indicates another problem, such as a leaking gasket or hose.
Dark brown coolant indicates rust in the cooling system.
Check the heater core temperature.
Lift the hood and check the temperature where the heater core hoses enter the heater core box.
The safest way to do this is with a non-contact infrared thermometer.
If the vehicle has a valve in one of the hoses, check its operation.
A stuck valve prevents coolant from flowing through the heater core.
Check for debris in the heater box.
Switch the thermostat from hot to cold and listen.
The specific diagnostic procedure varies with the vehicle.
If it receives power, peek if the blower motor is burned out.
If the blower doesn’t receive power, check that the blower fuse isn’t blown.
