1. Relay issue: There may be a problem with the blower motor relay, which is responsible for controlling the power supply to the blower. If the relay is stuck in the "on" position, it can cause the blower to run even when the ignition is off.
2. Faulty ignition switch: The ignition switch may not be fully turning off the power to the blower circuit. This can cause the blower to stay on even after the key is turned off.
3. Wiring problem: There may be a short circuit or other wiring issue that is causing power to flow to the blower motor even when it shouldn't be.
4. Blower motor issue: In rare cases, the blower motor itself may have a problem that causes it to stay running even when it's not supposed to.
It is important to identify and fix this problem as soon as possible to prevent unnecessary battery drain and potentially more serious electrical issues. If you are not comfortable troubleshooting electrical problems on your own, it would be best to have the vehicle inspected and repaired by a qualified mechanic.
