The two plug wires are basically a hot wire, and a ground. Use a 12 volt test light to find which is which. If you have the original switch for the 98 you can unplug it from the seat and plug it into the car harness (in the floor) and then into the newer seat plug. You will have to push forward on the old switch for the new seat switch to work, however you can trace witch of the four wires on the new seat is hot and which is ground using the test light while holding the old switch forward. Then you can simply cut the end of the old switch (leave enough wire to work with) and cut the four plug wire off the old switch as well. You will only need to use two wires and if you followed the instructions up to this point you will know which they are. I just swapped seats from an 03 to a 98 and this is how I wired them. It works great. Hope this helps.