1. Check the Fuse: Start with the simplest check. Your owner's manual will show you the fuse box location and which fuse controls the heater fan. Check if the fuse is blown (look for a broken filament). Replace it with a fuse of the same amperage if necessary.
2. Check the Blower Motor Resistor: This resistor controls the fan speeds. A faulty resistor will often result in no fan operation at all, or only the highest speed working (if at all). The location varies slightly depending on the S10's trim, but it's often located behind the glove box or under the dash. Accessing it may require removing the glove box or some trim panels. You can visually inspect it for damage (burn marks are a common sign) or test it with a multimeter if you have one. A faulty resistor needs replacement.
3. Check the Blower Motor: The blower motor itself could be faulty. This is more complex to test. You'll need to access the blower motor (often located behind the dash) and you might need a multimeter to check for voltage and continuity. If you're not comfortable with electrical work, it's best to have a mechanic handle this. A bad blower motor needs replacement.
4. Check the Blower Motor Switch: The switch on your dashboard could be the culprit. If you have multiple fan speeds, see if any work. If none work, the switch might be faulty and needs replacing.
5. Check the Wiring and Connections: Inspect all wiring and connectors related to the heater fan, blower motor, resistor, and switch for any damage, loose connections, or corrosion. Clean any corroded connections and repair or replace any damaged wiring.
6. Check the HVAC Control Module (Less Likely): In some cases, a problem with the HVAC control module can affect the fan. This is less common than the other problems, but it's possible. Diagnosing this is more complex and usually requires professional tools or a scan tool.
Before you start:
* Safety First: Disconnect the negative battery terminal before working on any electrical components.
* Consult a Repair Manual: A repair manual specific to your 2001 Chevy S10 will provide detailed diagrams and instructions. This will significantly help you locate components and understand the wiring.
* Professional Help: If you're not comfortable working on your vehicle's electrical system, it's best to take it to a qualified mechanic. Improper repairs can lead to further damage or safety hazards.
By systematically checking these components, you'll hopefully pinpoint the cause of your heater fan problem. Start with the simpler checks (fuse, resistor) before moving on to more complex ones (blower motor, switch, wiring).
