My dad has a 03 f-150 with electronic hubs for the 4wd. When you put in 4wd the dash light comes on, but the hubs wont lock. Any ideas?

 

not sure if this is the problem or not but i know the vaccum lines on these are a pretty common thing to go out, i recently had to replace mine on my '97 kinda sounds like the same thing

 

I replaced my vacuum lines for the same reason...Everything sounded allright when I switched to four wheel(i.e. transfer case engaged, light came on) but i still had no 4 wheel drive. I opened the hood and listened on the right side at the fire wall I had a vacuum leak(cracked lines). Check that