OF course the harness is a total pain & you still need to modify the door panel to install the switch. Also wiring up the relay in the fuse box as well.
The 1994 & 95 electric seat wiring harness part number 202-540-36-13 lists for $99.
The switch is color coded to the interior but list is $81. no matter what color that you need.
I helped doing that on 2 different W201 chassis(190E), but we had a donor car.
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)