Hi Scotty, my dad has a 1998 Mercedes CLK320 with over 210,000 miles. We noticed that sometimes the driver side power seat does not want to move forward or backward. The other movements work such as the headrest and backrest, but the chair moving forward and back does not always work. 

We first thought it was the control buttons located on the door itself so we went to the junkyard and got another module to control the seat, but it did not do anything. The power seats will work again for several weeks, then one day it does not want to cooperate for a while again. 

Could it be the seat motor itself? Just wondering because the other movements work?