2005 Hyundai Elantra Driver side Master window control

The driver side power window controler is not functioning properly. It still operates the driver side window ok but one by one it is losing control to the other windows Hit or miss at best on passanger window and not at all on either rear windows (which by the way have rarely been used either by the driver or passangers) I assume it is the switch at the driver control as each window switch at the respective window work fine. Questions are: how do I access the driver switches. And once accessed, are the switches fixable/cleanable or do they need to be replaced?
Thanks