* Faulty thermostat: A faulty thermostat may not open completely, restricting the flow of coolant to the heater core.
* Clogged heater core: The heater core may be clogged with debris, preventing air from flowing through it and absorbing heat.
* Faulty blend door: The blend door may not be opening or closing properly, preventing warm air from flowing into the cabin.
* Faulty blower motor: The blower motor may not be working properly, reducing the airflow through the heater core and preventing warm air from circulating through the cabin.
* Electrical issues: Faulty wiring or a blown fuse may prevent the heater from receiving power, or the switch that controls the heater may be malfunctioning.
