Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
If the SR S light is staying on then this would indicate a fault with the system which shouldn't effect the performance so the car is still safe to drive.
The quickest route to repair is to have the car plugged into a diagnostic machine which will read off the fault code stored in the ECU (providing the light is still on at this point) and indicate which sensor has failed or whether the fault is more serious.
what is quite common is that the electrical connections under the front seats has become corroded and so raised a fault with the seat airbag or seatbelt switch
I'd ensure that the ignition is switched off and then disconnect the plugs under the seat and spray both halves with switch or contact cleaner ( not WD40) and then plug and disconnect several times to try and 'scrub' the connectors clean of oxide
do you still need help?
Bear in mind that the site takes a deposit from you at the beginning and this is held by the site until you rate my answer at which point the cash is split between the site and the expert. I am only paid for my work on this question if you rate my answer, using the star system at the top of the screen. Please do not forget! Thank you