My 95' e320 wagon had the starter quit working and I'm certain it's not the starter.

It's got a new battery, and I replaced the wiring harness to the starter. It still won't turn over.

It's been suggested that the starter relay may be the issue and I need some good advise here.

Can someone tell me where the starter relay is, whether they believe that may be the problem, and if so how to get to it and take it out for replacement?

Thanks!