Do it yourself, change the master window switch on your Cadillac CTS, the model produced in 2005. You will need a flat head screwdriver and a new module switch from your local auto parts store. If you wish, you can use a small rag to wrap the screwdriver, in order to protect the plastic parts on the door panel.
The first thing you want to do is to pry out the plastic part of the window switch. Insert the flat head screwdriver on the extremity of the switch panel, to the interior of the car, as shown in the picture below. Pop it up some, then move to the side until it can be pulled out from the door panel.
After you do it, you will notice the two electrical harnesses that power up the switch panel, shown in the image below. Unplug the wires and remove the entire panel.
In order to replace the module, you have to separate it from the plastic cover. You can do it very easily using your fingers or the flat blade screwdriver, if you find it easier. After you do it, you can simply install the new module. Pop it back into the plastic cover, connect the two harnesses and install the whole assembly back into the door panel. Just press it inside until it is secured. These are the steps you have to follow, if you need to change the master window switch on your Cadillac CTS, made in 2005.