* Blower Motor Resistor: This is a common point of failure. The resistor regulates the fan speeds. A faulty resistor can cause the fan to only work on high speed (if at all), or not at all. It's relatively inexpensive and easy to replace, often located behind the glove box.
* Blower Motor itself: The motor might be failing. It could be worn out from age and use, or have internal electrical problems. This requires replacement of the blower motor itself, a more involved repair.
* Wiring and Connections: A broken wire, loose connection, or corroded terminal anywhere in the blower motor circuit can interrupt power. Check all wiring from the resistor to the motor, and the fuse.
* Fuse: A blown fuse is a simple and inexpensive fix. Check the fuse box (usually under the hood or in the passenger compartment) for a blown fuse related to the blower motor.
* Switch/Controls: The blower motor switch (or the climate control module in newer models) could be faulty. If the switch is malfunctioning, it may not be sending the correct signal to the motor. This is often diagnosed by testing the switch with a multimeter.
* Relay: Some Impala models use a relay to control the blower motor. A faulty relay prevents power from reaching the motor.
Troubleshooting Steps:
1. Check the fuses: This is the easiest first step.
2. Listen carefully: If you hear a clicking sound when you turn the blower on, it might indicate a relay problem or a problem with the switch.
3. Test the blower motor resistor: This is often a quick and inexpensive fix if the fan only works on high speed or not at all.
4. Inspect wiring and connections: Look for any broken, frayed, or corroded wires.
5. If all else fails, consult a repair manual or a mechanic: Diagnosing electrical problems can be complex, and a professional might be needed to pinpoint the exact problem.
Remember to always disconnect the negative battery terminal before working on any electrical components in your vehicle to prevent shorts and injury.
