Dodge Ram 2500 fwd will not lock

ok i just bought this truk a week ago an i went to try the 4wd out an the front hubs r not lockin in is there a relay or a wire that could b unhooked thats not tellin the front hubs to lock in when in 4wd any help would b great

what year and model? could be a bad 4wd actuator

its a 95 2500 w/ 5.9l engine from what i kno the driveshaft turns but the front wheels want lock an turn

dorman part number 600-202

Product:4WD ActuatorDescription:Plug Configuration:Contents:Includes gasket & clips (doesn't include harness)Brandorman - OE SolutionsApplication Notes:Front; 4WD; w/Dana 60 Front Axle; w/Disconnect

There was 2) 5.9s that year are you talking a 360 or a 359?  My truck froze up one winter back when my 4x4 was on the road and i put a Posi-Lok in.. By far the best upgrade i did, It allows you to engage 4wd after your stuck without grinding. You can feel the axle engage in hand rather then relying on vacuum. I wouldn't think twice about installing one in my next 4x4!!!Dodge Posi-Lok