Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
Hello and Welcome to Just Answer! this is a bit hard from internet connection but I will do my best.
1 st your airbag should go away after codes are cleared. disconnecting the seat has set fault codes in SRS module and on Mercedes vehicles light will not go away if code(s) are not cleared using diagnostic scanner.
Now about the seat. Seat control module is located under the seat. you do know that already as you have mentioned that there is power.
Red yellow cable has battery power all times and ground at brown wire.
the command to seat control unit is received from Driver door control unit(inside drivers door) commands are sent via CAN(controlled Area network) as data signals. Best thing to do is to use Mercedes Scanner and try to communicate with seat control module.
and read fault codes. You can also remove module, open it and inspect for water intrusion.
I am recommending that you never again should use steam cleaning. As there are electronic units under carpet. Front prefuse box and front Sam module are located under carpet on passenger side.
If you see water damage to the board you can wash it with hot water and soap using too brash.
as it had happened recently damage will be minimal. then blow dry it( do not overhead the board as some elements can get loose)
replace and retest.
please check and get back to me. I have mentioned Mercedes scanner because all other aftermarker diagnostic tools are very lmited.
there are some good once but nothing gets close to Factory equipment. ask around nowadays many shops have Mercedes Xentry DAS scanner.