[dj_hobbes]

I did a forum search and also looked myself in the paneling for the "plug" that I connect the harness for the towing prep package that was included with my 2002 Highlander.
Can someone help me out and point me in the right direction of where I can find it?

 

[sportal]

It is located under the plastic panels in the rear cargo area under the floor.

1st, remove the plastic panel underneath the center section that covers the bolt for lowering the spare.
2nd, remove the plastic panel beneath the left storage compartment in the floor of the cargo area.

You'll find a molex style connector for the hitch wiring harness, and a small black circle for bringing the cable to the outside.