been getting a lot of responses to m problem with my 1998 c280 mercedes benz. I think the problems is the k40 relay module. is this a dealer only part? I checked all the fuzes in the glove compartment. All of a sudden last month, my windows, my trunk, my sunroof, my directionals wont work. The trunk wont work manually with the key either. I figure from all the reading i have done, the problem is the k40 relay. changing this out, some people say only takes 10 minutes. has anyone else had to change the k40 relay?