When an s13 sr20 harness is used in an s14, the power plugs that goes to the gray and brown (engine bay where the battery is at) plug gets pulled back into the interior of the car to wire up to the F3 plug (
http://img.photobucket.com/albums/v2...B/100_4130.jpg) (its the plug next to ECU in an s14). Look near your ECU plug and you should find a smaller white plug. this is the s14 power plug. just cut it off and pull the harness back to where it would be in the engine bay. cut off your ka24 engine harness gray and brown plug and wire it to the wires i just mentioned. google for the wire diagram.
the dash plug should be untouched unless they cut it off and solder it directly to the F3 plug. if it's been modified, then just grab one off your old ka harness and solder up the wires. all colors match.
hope that make sense.