I am new to this Forum and I searched but cannot find the answer to my question. I just completed a 2WD to 4WD conversion on my 2005 Ex by swapping in the axles from a 2006 F250, and the transmission/transfer case. I was able to get the ESOF working after getting a wiring harness, swapping in the GEM module and replacing the switch (If no one here knows this; Ford changed the resistor values on the 4WD selector switch at some point… I am handy with a solding iron so I swapped out resistors to make it work)
I am very happy that my 4wd works perfectly, but I have no indicator lights! It is clearly shifting into 4wd, because the big beast does not like to make turns on pavement in 4wd at all! But that is a good thing because I know the transfer case is shifting. 4low is also obvious by the revs. I just need some help with the indicator lights. A few questions:
1) Does anyone know if the instrument cluster is the same on 4wd vs 2wd models? Are the 4X4 lights even present on my truck?
2) I have forscan and checked if there were any simple switches to “tell” the truck it is now a 4wd, but none are present. Does anyone have as-built files for the PCM and IC modules for a 4wd 2005 Excursion with a 6.0L? I would like to compare these in Forscan.
Thank you in advance for any help!

 

Actually, it's just a value you have to turn on using IDS or maybe even forscan. On my 2001 I would have to program the GEM to tell it that it's now a 4wd truck, but in case that didn't work, I have the GEM for a 4wd truck that lights up the lights on the dash. On your 2005 Excursion, it's a matter of logging into the ABS module with IDS or Forscan and changing a value. The light should come on when you flip the switch .

 

I am not sure I checked the ABS module for that switch. I will check it out tonight in Forscan and see if it is there.
I don't have IDS, is that something that is available to a Do it yourselfer, or something I would need a shop to do?

 

There is no option in Forscan to change to 4X4. I checked all the modules. There are not many programmable features at all listed, that is why I was hoping I could change AS-Built values.

 

There is no difference in the PCM between a 4x2 and a 4x4. All PCMs can handle both.

 

So, if the PCM can handle it and there is nothing to program differently, any recommendations on how to get the indicator lights working? I used the 4X4 yesterday, an it works great. was able to park my boat despite the wet grass. I am 100% certain that my transfer case is shifting, even got a chance to see the rear limited-slip kick in. But I have no indicator lights whatsoever. Even the MSS light does not come on in any position.

 

curious about this. Your 2005 doesn't have a GEM. 2002+ shifted over. It has a VSM, and so did the Superduty you grabbed the module from. the superduty version will work, but stuff will be wonky (lights, door sensors, key fob, etc)

Did you program the as-built data in the new VSM? If not, what is/is not working (besides 4x4 indicators) right now?

 

So it doesn't have a General Electronic Module (GEM) to control everything like the Excursions before 2002. You are right they switched over to a Module. But it does have a 4X4 Controller, which in Forscan it calls a GEM. It was confusion to me too when I started researching this because prior to 2002 people did lots of stuff with the GEM. Most people refer to what I am talking about as the 4X4 Controller, which was the same on the 2006 F250, mine was 2WD so it didn't have one, but the wiring harness was there, just on dummy plugs. I didn't change out the module (Or PCM) I kept the one from the 05 Excursion, but I have both and am considering that as an option. I am not sure what else I might have to adjust if I switch out the module, but VIN and milegage, would be a start, and that seems like a PITA when I am so close to complete success.

*Update* I pulled off the Vacuum Solenoid from the 2006 F250 and installed it in the Excursion. I don't plan on connecting it since I can override the manual hubs, but I thought if the 4X4 controller "sees" it there, then that is 2 less error codes I have to sort out. I haven't had a chance to connect the computer and read codes, but plan to tonight. I did use the truck a lot this weekend, pulled my 30' camper and parked it in a grass lot...without the low range 4X4 working, this would not have been possible...but it works well! This truck is a beast.

 

One other thing I didn't mention. In 2006 Ford switched to a bigger relay box under the hood, with more fuses and relays, I think it combines two smaller boxes from the 2005, Prior to that the 4X4 had a simple relay box with only the 2 relays for the transfer case, then a second box for something else (I forget what) I went to the junkyard and got a wiring harness from a F250 that worked (probably a 2005 or something close) because I didn't want to get into all the other wiring. The harness from the 2006 had 1 connector that was different, that goes into that fuse box. I am pretty sure I would have gone down a pretty deep rabbit hole trying to make the 2006 harness work on my 2005 truck. With this combined electrical junction box under the hood Ford changed the harness that serves the transmission/transfer case.

 

thanks for updating us. That is weird with the module names. But then again, it's Ford. They've done some really odd stuff over the years.

be careful with the Superduty harness. The early 6.0 with 5R110 trans controller (TCM) is part of the PCM for all X's and some Superduty. I don't know when it changed, but somewhere after 2005 it seems that Ford split the TCM/PCM apart and located the TCM on the frame-rail next to the trans. That may have something to do with the harness differences you're seeing

 

Sorry to bump this old thread, maybe someone can help guide me. I’m swapping my 2002 7.3 Excursion to 4x4, using a manual t-case and manual hubs. I just want the 4x4 light on the dash to work. Is there anything I need to program for that? I have Forscan and even IDS if needed. Also, the manual t-case I have has a connector on it, I’m assuming for the 4x4 light. Will my 2wd factory harness have a plug for it? I haven’t looked yet. I read that trucks have a dummy plug there for the tcase, but not sure about Excursions as they were never available with a manual Tcase (as far as I know)