I believe you may have wired 2 of the three wires in the headlight harness adapter the worng way. You may have reversed the hi/lo signal wires which are now messing with the position of the control stalk for you highs.
I ordered a 9007 hi/lo kit from them a week ago and they should be at my doorstep in a few hours. Albeit this kit isn't for my stang, but for my dad's Econoline van the procedure for wiring will likely be the same, since its all FoMoCo stuff. Ill try to snap a couple of pics or something and post back to try to clear up any confusion on how to wire these things properly.
EDIT: While I'm at it I'll try to post a brief review of this kit since I've installed over 50 kits on my own and friends vehicles, I'd like to see how the initial quality/packaging/bulb quality is on these so that people know the heads up when ordering form
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