If your 2009 Nissan Versa's air conditioner is only working on the two low speeds (1 and 2) and the fan does not blow any air at all on speeds 3 and 4, there are a few potential issues that could be causing this problem. Here are some common troubleshooting steps to help you identify and potentially fix the issue:
Blower Motor Resistor
The most likely culprit for this issue is a faulty blower motor resistor. The blower motor resistor is responsible for controlling the fan speed settings. When it fails, it often leads to the fan only working on the lower speeds. The resistor is usually located near the blower motor under the dashboard. Replacing the blower motor resistor/control module should resolve the problem.
Blower Motor
It's also possible that the blower motor itself is faulty. If the blower motor has gone bad, it may not work on certain speeds, resulting in the lack of airflow on higher settings. A faulty blower motor would require replacement to restore proper operation.
HVAC Control Unit
There's a slight possibility that the HVAC control unit (the fan speed control knob or button) could be malfunctioning, preventing the higher fan speeds from working. Inspect the control unit for any visible damage or issues and consider replacing it if needed.
Wiring and Connections
It's also essential to check the wiring and connections to the blower motor and blower motor resistor. Loose or damaged connections can lead to a loss of power, causing the issue. Ensure all electrical connections are secure and free from corrosion.
