the driver's seat upward/downward adj is broken and looking for a DIY instruction on how to repair it.thank you.

Try cleaning the switches for the seat in the door...
DIY - w126 Memory Seat Switch disassembly and cleaning

The switch is fine as I can hear the motor run but it sounds like the cable is not engaging properly. It is the back of the bottom cushion upward/downward adjustment that is not working. All others are working properly.