For the contact points inside the power window switch on the driver's side, grease may form a bridge between the terminals, because the method of applying it was not appropriate. Therefore, if abrasion powder generated by the contact adheres to the grease and accumulates on the progressive use of the switch, the terminals may short circuit. If this occurs, the power window may malfunction, and in the worst case, smoke and/or spark could occur, leading to a fire.
