Has anyone replace a new motor for their Toyota sienna sliding door?

I have 2004 toyota sienna van and the sliding door is not working. The dealership charges $2000 to fix it. I want to fix it at home to save money. Any advices how to replace a a new motor would greatly appreciated. Also where can I buy a cheap motor.Has anyone replace a new motor for their Toyota sienna sliding door?How about using stepper motors??