Unplugged idle control box changes nothing. normal?
 

I am trying to fix the high idle on my 1984 500SEL. It idles consistently around 1000rpm's. I removed the idle control box from the firewall and opened it up to see if any of the contacts had burned off. Everything looked fine. I decided on a whim to see if the car would start without it, and to my surprise it idled just the same! Does this mean that the idle control box is shot? Unplugging the Idle control valve gives a surge in RPM's so i am assuming that it is working ok.

Thanks

Rory