help with 4x4

hi can use soom help i have a 98 150 5.4 motor 4wd 3 door ext cab now havent used truck for about 3 months shifter rusted and floor shifter for 4x4 same spryed down linkage now free but no 4x4 tested to see 12v to vacuum solenoid both have 12v checked vac lines and reservoid ok checked actuator ok checked trs in transfer case ok checked all fuses ok now on the engage and dissengage solenoids have two wire plug one 12v and the other to the G.E.M that grounds the solenoids 2wheel ok 4wheel has 12v but when put in 4wheel hi no click can the relay on the G.E.M be bad and is it replaceable also did i miss anything can realy use some help
thanks dom