If it is your A/C or heater fan that stays on when you turn off engine, it is the heater fan or blower motor regulator which is often part of then fan. You can dis-connect the battery and simply replace it.
Jan 20, 2013 at 11:29 AM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.