Originally Posted by ATOM
it could be the IWE solenoid not working, ripped vacuum line, actuators need replacing. there are only a few things that can cause the 4x4 system not to engage..
vacuum checking the 4x4 system is the easy way to troubleshoot what is the trouble.
^ what he said! It could be any 1, or all of those things. I have seen several posts on this topic and the vacuum lines seem to be a common problem with getting moisture inside the lines.
1996 F150 Scab longbed, 5.8L, 4x4, 31x10.5 tires, 212k miles and counting. step bars, low-profile tool box, Euro-clear turn signals & headlights, Euro taillights, vent visors, class III Reese hitch, Tekonsha brake controller.
"when you have a hammer in your hand, everything looks like a nail."