where is the purge valve located in my 2004 toyota highlander 6cyl.

Purge valve is located on a mounting bracket bolted on the front of the intake manifold. On a 4 cylinder its bolted on the firewall behind the throttle body.

I had the very same problem with my vehicle. This year model had problems with the bulb socket you need to replace it. The part is about $3 and can only be purchased at Toyota.