I was just about to post that. I added DRL's to my car and had the same problem. When I put in my Hiper 9005 high beams I guess I didnt put the connector on very well and it came loose. So one day after I purchased the Cuzos, I went to change them out and saw the problem. Havent had any more problems since. So I guess a bad bulb would have given you the same effect.

BLUE-1999 Contour SE-Zetec-Clear Corner Lights-Nokya 3157 corner bulbs-Kenwood Exelon X815-2-12" Pioneers-4 6x8 3-way pioneers-Cuzo 9006's & 9005's-Glowing Ford Emblem On Decklid-Blue Interior lights-Alarm W/ Remote Starter-
Daytime Running Lights-CTA Intake-Winshiel Nozzle Lights-Audi A6 Side Marker Lights-Mesh Grilles (Good Ole Gutter Guard)-Just Added SVT Exaust
Thanks For The Idea CEG'ers !!!