Here's why it's likely the resistor:
* Higher speeds bypass the resistor: Higher speeds (like 3 and 4) often bypass the resistor altogether, drawing power directly from the battery. This is why they work.
* Lower speeds rely on the resistor: Lower speeds (1 and 2) use the resistor to reduce the voltage to the motor. If the resistor is faulty (burned out, damaged, etc.), it won't allow sufficient current to flow at those lower speeds.
Other less likely possibilities, though still worth considering, include:
* Blower motor itself: A failing blower motor might struggle to spin at lower speeds but manage at higher speeds where more power is available.
* Wiring issues: A short circuit or break in the wiring related to the lower speeds could also be the culprit.
* Fuse or relay: Although less common in this specific scenario, a blown fuse or faulty relay related to the blower motor could affect certain speeds.
In short: The most probable cause is a faulty blower motor resistor. It's relatively inexpensive and easy to replace, often accessible under the dashboard. You can find diagrams and videos online showing how to access and replace it for your specific year and model Sebring. However, if you are not comfortable working on your car, it's best to take it to a mechanic.
