Ok, first things first. I am new here, just bought me a 2004 Ford F150 Supercrew Lariat 5.4 4x4. So I do not know a whole lot about these trucks so here it goes. I went to use the 4WD and turn the switch but nothing happens at all, just trun it and no noise nothing. So I checked the fuses and fuse #111 is blown. So I replace it and it blows again...soo any ideas of what would be causeing this? please let me know!
The relays are CW and CCW, not the motor. They control Clockwise and Counterclockwise movement of the Tcase motor respectively. Pull both relays and check for a short to ground at the reciever for pin 30 to each. If they do, you're issue is in the wires to the tcase motor (nicked or crushed) or the tcase motor yourself (cross your fingers it's not that. If they don't, it's probably one of the $3 relays.
I'm having the same problem with my 4x4 Relay fuse blowing. I checked for a ground with both relays pulled and it was good. I have been unable to find a service manual. I don't want to buy a book because I prefer being able to search using the electronic version.
So is it a high possibility that the problem is a relay? First it seemed like the fuse was blowing when I went from 4HI back to 2HI, but after replacing the fuse and having it work a couple of days, it blew when I went to test it going from 2HI to 4HI. This was at night and I noticed a slight dim in the lights also.