Under the throttle body, toward the firewall, body is brown plastic. Known to fail early. There's a site (dsmisc.com) who sells genuine Mitsu units for around $135, and get the new oring, too. Testing procedure in the fsm, basically testing for correct ohms across the terminals. Usually fails due to deteriorated insulation in the internal coils, usually caused by using a cleaner on the throttle body without plugging the hole to the ISC.

It comes out by unpluging the connector and removing two 10mm bolts (with phead screw slots, too, IIRC).

Not responsible for advice not taken...