My question is how do I fix the electric windows and seats they stopped working?

Normally a bad ground. Ground is supplied from a junction in a black plastic box..The box is located in a wiring harness channel under the plastic trim and carpet in the floor under the bottom edge of the drivers door. There is one screw behind the emergency brake pedal to get that trim off, then the straight piece of trim will pry off. The box is near the emergency brake end of the channel and may have electrical tape around it. Get the tape off and open the box. You will find seven ground wires and connectors attached to a metal plate. Even if they don't look corroded they are not making good contact and causing your problem with the windows, seat , and ignition. You can try cleaning the connectors and metal plate they attach to, and try your windows and seat. I ended up removing the connectors, stripping the wires and soldering them together. Car starts and runs great as this was partially grounding out the ignition when the contacts were bad. Note: There is the same setup on the passenger side, but your problem is with the drivers side. Good luck. It just cleared up the same problems on my 98 LSS.