It's not in the FSM. You need the 2002 Toyota 4Runner Electrical Wiring Diagram Manual. I just did a google search and saw one on ebay for $45. Very handy to have. Here's a Dropbox link to a 2000 4Runner Wiring Diagram Manual which might be close enough.
2000 Toyota 4Runner Wiring Diagram
Dropbox - 2000 4Runner Electrical Wiring Diagram (EWD383U) - Printable - Simplify your life