Driver’s seat won’t move forward
 

My father borrowed the 1984 190D with electric seats. He moved the driver’s seat all the way back, and it won’t move forward from that rear most position. The right side is moving forward, but the left side moves forward just a bit and then stops as if something is jamming the rail. Nothing is. The seat will raise up/down, front edge tilt up/down, and the rear edge tilt up/down. When you push the switch to move the seat forwards, there is motor noise. I cannot find any schematics for the power seat.

It almost looks like there is one motor for that forward/back movement that drives two cables, one to the left rail and the other to the right.

Has anyone tackled this problem? Thanks, Dave