Lets start with the bad design of the windows. The windows have to much play! They move side to side a little when you roll them up and down. This, in my opinion, causes the window regulators to wear down and eventually go bad. You have to take off the door panels and while someone else holds the window up you unbolt the regulator. Some of the bolts are in tight places so you may have to be crafty to get to them. A 1/4 inch drive socket set will work. Bolt the new regulator in. You will probably need new door panel clips (I found mine on ebay) because you will break some of them when you take the door panel off. So buy them before you do any work. Seems like we needed a torques bit for something. I can't remember all the tools needed but it took about 45 minutes to change each one and we didn't know what we were doing. After I fixed my windows I saw 2 different caddies with there windows taped up. Then my neighbor bought one and one of his windows is doing the same thing so it must be a common problem with Devilles. Good Luck!!!