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My '92 E150 & '98 F150 both had plugs near steering column to help install trailer brake controls. The Econoline set up provides regualr 2 bulb trailer lights from it's seperate amber turn signal system. However both had Towing Packages & I'm doubt this would've been part of standard "stock wiring".
I'd expect an '03 f350 would have such a plug. Look for a 6 pole, usually white, connector, about the size of a sugar cube, near steering column, just behind knee panel.
The mysterious part for me has been the pigtail that is used to plug in it. I've read that FORD placed this pigtail inside new pickups, presumably as part of the Towing Package, but they seem to disappear w/o a trace. Ebay usually has a few, expect to pay ~$15 to get 1.
You can get a cable to mate with the factory trailer brake connector with some brake controllers. Tekonsha had mating cables available for the Prodigy controller. Check the RV supply sites. Just do a google search on "trailer Brakes".
The Prodigy is a great controller. I wish I had gotten one sooner....