* Low Coolant: This is the *most common* cause. Check the coolant level in the overflow reservoir. If it's low, you need to add coolant (the correct 50/50 mix of antifreeze and distilled water). A low level could indicate a leak somewhere in the cooling system.
* Faulty Thermostat: The thermostat regulates coolant flow. If it's stuck closed, coolant won't circulate properly, preventing the engine from reaching operating temperature and thus producing heat.
* Water Pump: The water pump circulates the coolant. A malfunctioning water pump won't move the coolant, resulting in no heat. You might hear unusual noises from the pump if it's failing.
* Bleeding the Cooling System: Air pockets in the cooling system can prevent proper circulation. The system might need to be bled to remove these air pockets. This usually involves opening specific bleed valves.
* Heater Core: The heater core is a small radiator located inside the car that warms the air. A clogged or leaking heater core will prevent heat from reaching the cabin. A leak will often result in a musty smell or wet carpet.
* Heater Control Valve: This valve controls the flow of coolant to the heater core. If it's malfunctioning or stuck closed, no coolant will reach the heater core.
* Blown Fuse or Relay: Check the fuses and relays related to the heater system in the fuse box.
* Faulty Blower Motor: This motor blows air through the vents. If it's not working, you won't get any air, hot or cold. Check the blower motor fuse first.
* Temperature Blend Door Actuator: This component controls the mix of hot and cold air. A malfunctioning actuator might be stuck in the cold position.
Troubleshooting Steps:
1. Check Coolant Level: The absolute first thing to do.
2. Check for Leaks: Inspect hoses, clamps, and the radiator for any leaks.
3. Feel the Heater Hoses: When the engine is warm, feel the hoses leading to and from the heater core. They should both be hot. If one is cold, there's a problem with flow to or from the heater core.
4. Check the Blower Motor: Does the fan work on all speeds?
5. Check Fuses and Relays: Consult your owner's manual for the correct fuses and relays.
6. Consult a Repair Manual: A repair manual specific to your 1998 Chrysler Sebring convertible will provide detailed diagrams and troubleshooting steps.
If you're not comfortable working on your car yourself, it's best to take it to a qualified mechanic for diagnosis and repair. The problem could be simple (low coolant) or more complex (a failed heater core).
