Starter location on 1997 e350 super duty class c?

I agree with what Dr.Quick said except that before I did anything else, I'd get someone to turn the ignition to the start position and hold it there, and, assuming there's no response from the starter, take something like a small hammer or crescent wrench and lightly but firmly rap the solenoid next to the battery and maybe you'll get a response. If it works, replace that solenoid with a good quality brand name one. I had the same problem on my Ford E350 van.