It is located under the air filter housing. Not sure what why you are replacing it but here are some hints. Try tapping / banging on it to see if a relay inside is stuck. If you find that is the problem, these can be replaced. If you want to save the $140, drill the rivets amd open the box. Radio shack sells these relays. They need a little modification but it works. They sell for $7 a piece. I replaced all 3 for safe measures. By the way, the wiring plug is held in by that little bolt on the harness. Good luck.