1. Faulty Blower Motor Resistor: The blower motor resistor regulates the speed of the blower fan. A faulty resistor can cause the fan to stay on continuously. Check the resistor and replace it if necessary.
2. Ignition Switch Problem: A malfunctioning ignition switch might not be properly interrupting power to the blower fan when the key is turned off. Have the ignition switch inspected and repaired/replaced if faulty.
3. Faulty Wiring or Shorts: There might be a short circuit or a wiring issue in the blower fan circuit that's causing it to remain active. Inspect the wiring, connectors, and grounds related to the blower motor and fan speed control system.
4. Control Module Issue: In some cases, a problem with the climate control module or other electronic control unit (ECU) responsible for the blower fan's operation could lead to it staying on continuously. Have the control modules scanned for fault codes and check for any software updates.
5. Vacuum Leak: On some models, the blower motor control system may use a vacuum line to regulate the fan's operation. A vacuum leak or a problem with the vacuum switching system could prevent the fan from turning off properly.
If you're unable to identify the cause and resolve the issue, it's best to seek assistance from a qualified mechanic who can diagnose and repair the blower fan problem.
