I have an 05 F-150, 5.4. When I switch it into 4 high I can hear it click in but the front wheels aren't engaging. When I tried 4 low I could feel that the rear end was in low but still nothing from the front wheels. This seems odd since I just got the truck last summer with low miles and seemingly mint condition. This was the first time I needed 4wd. Can someone tell me what this could be? Thanks.

 

after reading through some related threads, I guess i'll try the hitting the transfer motor with a hammer first, see if that frees it up. the lights come on a nd i can hear it working, just no engagement.

 

I had the same problem, and I had to replace a hub.