my c/s button won't change

Question by debbiestringer posted 7 months 3 weeks ago in E-Class

My c/s button won't change, i've pushed it many times but it won't work. what is it controlled by? fuse? or if its gummed up how can I fix it myself? Is there anything I could use to clean it? I bought my car used and I've never spilled anything on it but wouldn't know about the previous owner