I bought a 2003 F250 6.0 diesel used and the 4x4 ESOF has never worked. I have been researching and troubleshooting the issue for quite some time now. Since the vehicle is a restored salvage that I bought used I can't assume all of the parts are on the vehicle in order for the 4x4 ESOF to work. My issue currently is that I know that the two relays for the shift motor are good (bench tested) and are not getting activated from either the GEM or the 4X4 Control Module. The problem I have is that I have read conflicting information about the 2003 F250 as to whether it has a GEM or the 4x4 Control Module. From what I can find out Ford must have switched from GEM to the 4x4 Control Module either in 2003 or 2004. I have pulled the glove box and looked behind it and I don't see anything that looks like a 4x4 Control Module behind it. Before I go to the time to pull the fuse panel to see if there is a GEM mounted to the back of it I was hoping someone could clarify exactly what the 2003 F250s with ESOF 4x4 were shipped with, a GEM or a 4x4 Control Module? As you may can tell I'm a little frustrated and any help would be appreciated.

 

Did you ever figure this out. 2003 Excursion 6.8 v10 No light to 4x4 switch , no 4x4

 

Yes I actually did figure this one out. I no longer have the 2003 F250 but what the 4x4 problem turned out to be was the 4x4 Control Module. The 4x4 Control Module was located behind the glove box. I had to pull the glove box out and look up above where the glove box is located when closed and there is a black plastic box that has two bolts holding it in place. It also has 4 large cable connection going into it on the side and on the end closest to the firewall. These are a little tricky to unplug if you have large hands but it is doable. Once you have the box out it is held together by several plastic clips that you can release with a small screwdriver. Once I found the 4x4 Control Module I was able to get the part number off the board and I located one that was an exact match. Replaced it and re-installed the 4x4 Control Module and I then had both 4x4H and 4x4L (that shows up on the display as "Low"). I hope this helps.

 

Thanks for info. I had windshield leak. I think that may be it. Thanks again.

 

After I pulled the cover off the 4x4 Control Module I could see where water had made it into the module and shorted out in a couple of places on the board. The replacement board I put in, I sprayed it with electronic insulation spray I picked up from a local electronic parts store. This virtually waterproofed the solder side of the board that faces up when mounted, just in case more water made it on the board it wouldn't short out.