Originally Posted by 97 SL320

The 98 and up W202 has a CAN system for many functions. I haven't researched these, only my 97. Given both don't work, there is a global problem, find the seat controller and make sure it is getting power / CAN communication. If this is a one driver car, and a solution can't be found, I'd jumper the motors to get things into position.

You really need a wiring diagram for this car for current and future repairs.

I replaced the headliner on my 97 during a windshield replacement, comes out the front very easily. It is possible to remove with glass in but requires seat removal and bending. Once the headliner starts to peel ( on the c pillars on mine ) it deteriorates very rapidly. The sun roof vents on mine disintegrated and I didn't replace them, had the shop cover over them. Also put white vinyl on inside of glass to block sun.

Also with headliner out, replace the 4 sun roof drain hoses and extend them outside of the rocker panel. Yes, they drain into the rockers. The stock ones deteriorate above the headliner leading to leaks. Just buy them at the dealer, they are metric and thin wall making them difficult to source in the US. Replacements are cut to fit leaving enough to get outside of the rocker.