- Check the coolant level in your radiator and reservoir
- If the level is low, add more coolant and bleed any air from the system
2. Faulty Thermostat
- A stuck-closed thermostat will prevent coolant from flowing through the heater core
- Replace the thermostat if it is stuck closed
3. Clogged Heater Core
- A clogged heater core will restrict the flow of coolant and reduce heat output
- Flush the heater core with water and compressed air to remove any blockages
4. Broken Heater Valve
- A broken heater valve will prevent coolant from flowing through the heater core
- Test the heater valve and replace it if necessary
5. Electrical Problem
- Check the electrical connection to the heater motor and control switch
- Test the heater motor and control switch and replace them if necessary
6. Incorrect Temperature Setting
- Make sure the temperature setting is turned up high enough
- Check the climate control settings and make sure the heater is turned on
