Irritating Turn signal issue on my 2001 Windstar

[jsieao]

I am having difficulty figuring out this problem. My right front turn signal isn't working. Bulbs are good, socket is good, and can't find any breaks in the wire.
My mechanic is stumped at the moment, and he is investigating further as well. When the turn signal is initiated the cornering light comes on but the turn signal does not. All other turn signals and lights work fine. Any ideas??
I just went out and poked around a little bit, and note that if the parking lights are turned on, the right front bulb illuminates.