On an s4 the connection for the powersteering plug is on the engine harness (the one with battery terminals attached to it) and the plug should be right near the fuse box in the engine compartment (at least on an s4 it is) some people think an engine harness is what attaches to the actual engine but the correct term for that is the "emissions harness"

Iluvmyrx7.com

it is a site with FULL Factory manuals for all rx7s including yours. It is in PDF format so you can download it. Hope that helps some.

-Tony