GM Service Manual Online
For 1990-2009 cars only

With the ignition switch in either the RUN or START position, the voltage is applied to both the power window switch through the closed contacts of relay  When you press the right hand power window switch to the UP position, voltage is applied to one side of the motor through the now closed UP contacts of the switch, and the other side of the motor connects to G105 through the now closed DOWN contacts of the switch. This causes the motor to turn and raise the window. When the switch is released, the contacts return to their neutral state and the motor stops. When you press the right hand power window switch to the DOWN position, voltage is now applied to one side of the motor through the now closed DOWN contact and the other side of the motor is connected to G105 through the now closed UP contact. This causes the motor to turn in the opposite direction which causes the window to go down.

The operation of the driver's right hand power window switch is similar to the right power window switch with the exception that the motor and ground leads of this switch are connected to the motor and G205 through the right hand power window switch. In all other ways the operation of the switches are the same.