Hello everyone ? happy to discover this site.I need your help, I owned a 89 420sel, I believe is also known as w126, many months ago the electric power-seat would work intermittently, but now it not working at all, would anybody know what the problem, is it just the relay , switch or ???.
I've tried to interchange all similar silver-color-relay in the fuse box,on the left engine compartment, but no luck. both front seat are not working.
Please tell me what to do ? thank you in advance !!!!
mark

 

in my 99 c280, the relay that is responsible for the power-seats is called the comfort relay, and it is located in the trunk, above the fuel tank. there are 2 relays there, and it is the one that is at the farthest reach.

i had the same problem, replaced the relay, and now the seats are moving fine.