1. Fan Motor Issues:
* Blown Fuse: Check the fuse box (usually under the hood or under the dash) for a blown fuse related to the blower motor. Your owner's manual will show you the correct fuse.
* Blower Motor Resistor: This component controls the fan speeds. A faulty resistor can prevent the fan from working at any speed, or only at the highest speed. It's often located behind the glove box.
* Blower Motor Itself: The motor could be faulty and need replacement. This is less common but possible. You might hear a clicking sound if the motor is trying to start but failing.
* Wiring Issues: Check the wiring harness leading to the blower motor for any breaks, loose connections, or corrosion.
2. HVAC System Issues:
* Blend Door Problems: These control the mix of hot and cold air. A malfunctioning blend door could be stuck in the cold position, even if the heater core is working.
* Heater Core Issues: The heater core itself could be clogged, leaking, or failing. This would prevent hot coolant from reaching the heater core, resulting in no hot air. A leak would be indicated by a sweet smell in the cabin or low coolant levels.
* Thermostat Issues: A faulty thermostat might not be allowing coolant to reach the appropriate temperature, preventing heat from being generated.
3. Control Issues:
* Switch Problems: The HVAC controls (switches or buttons) could be faulty. Try checking all settings, including fan speed and temperature.
* Vacuum Leaks: Some older vehicles use vacuum lines to control components of the HVAC system. Leaks in these lines can prevent proper operation.
Troubleshooting Steps:
1. Start with the simplest: Check the fuses first.
2. Listen carefully: Can you hear any clicking or whirring noises coming from the blower motor area?
3. Inspect visually: Look for any obvious wiring problems or loose connections.
4. Check the coolant level: Low coolant could indicate a heater core leak.
5. Test the blower motor resistor (if accessible): You can often test its resistance with a multimeter.
6. Consult a repair manual: A repair manual specific to your 1996 Chevy S-10 will provide detailed diagrams and troubleshooting steps.
If you're not comfortable working on your vehicle's electrical system, it's best to take it to a qualified mechanic for diagnosis and repair. Improperly handling electrical components can lead to further damage or injury.
