2001 Mercedes Benz C240

This model is notorious for this problem. The common problem is both the driver and passanger front seat control modules do not turn off when the vehicle shuts down and hence drains the battery. The control modules are located directly under both seats. They are the black boxes toward the front. You can unplug these modules (one electrical plug, slides off) and see if it stops the battery discharge. However by unplugging the modules your seats will loose their memory and will be inoperative while unplugged.