more than likely it is the multifunction switch. it is the black stalk that control the wipers and blinkers and high beams. 99% of the time this is the cause. also check the headlight switch. the go as well, just not as often. headlight switch can be had aftermarket pretty cheap, amd the mfs is a dealer only part. if you need one, lmk, i can get you a good deal on one.
2003 Ford Expedition: 5.4L, harley supercharger, 2.93 upper pulley, 4lb lower pulley, c&l plenum, jlp cai, LFP SBTB, FTSP, Magnaflow 3" catback, Eclipse AVN-5510, white face gauges, cobalt c2 boost gauge, ddm hid's, 379 rwhp, 465 rwtq sold 11/3/12
2009 Ford Flex Limited AWD