just bought truck 01 superduty 5.4, elec switch on dash, when I was test driving it it worked now it doesn't, 4wd light in dash lights up when turn key on, but after started it doesn't come on switch 4wd to high or low ??, I unhooked battery no help, the switch is illuminated from headlight switch

 

well not that im gettinging any help here 5000 views no response, but I changed motor on tc, with a new 1 no help, so either the switch on the dash, or I assume gem module, as theres no 4wd module like on explorers behind glove box?