Automobile markets are so fierce in the world market that every major manufacturer assure the buyer of the car by give a provocative warranty plan for their cars. For instance Hyundai motor company offer 10 years and 100,000 miles of warranty whichever comes first. But in order for this effort to be successful every critical component such as window switch has to be proven to be reliable in an adverse environment. Therefore, in this article reliability assessment criteria for window switch are established in terms of basic performance test, environment test and life test.