update: 4wd controle module fixed the problem. when working correctly, you see the 4 high and 4 low lights come on momentarily as vehicle is started. also when you shift to 4 high or low you can hear that module click. i priced the module at several places and got the best deal at autopartstomorrow.com ( brand new motorcraft module for 123.00 ) labeled as a TM101 shift control module. thanks again to rrgone for the electrical schematics