I have removed all of the seats and carpet from my truck this weekend. Had an upholstery cleaning marathon. Everything, much to my surprise is perfect. No rips or stains that could not be removed. Absolutely no floor pan rust.

When I removed the passengers side kick panel I found several electrical connections. I always like to learn something new about my truck.

Can anyone tell me what the grey box is on the left side of the photo?

 

That's the ESOF (Electronic Shift On The Fly) controller. It controls the electrically shifted transfer case for your 4x4. The red light and button on the side are used to activate a self-test sequence. You have to unplug one of the connectors, switch the key on, then wait for the red light. I don't remember how to interpret it off the top of my head but it's something like if the light comes on for 4 seconds and goes out then all is well and if it stays on longer than that then the module has failed. Something like that.

The small black box with the red button, to the right of the ESOF controller, is your inertial fuel cutoff switch. Smack something hard enough with the truck and the red button will pop up and cut power to the fuel pumps. You can also whack the side of the switch, or use your ignition key in that slot just below the red button, to pop the button up manually. This is good for when you park in not-so-nice areas and worry bout your truck being stolen. It won't stop a professional thief (they have tow trucks) but it will stop the punk kid that thinks he can "start any Ford with a screwdriver" from going for a joyride.

 

Also known as a GEM module, (general electronics module). Programmable device and vehicle specific. Like Dixie said, controls the electronic shift transfer case. Myself, I much prefer the floor mounted shifter!

 

No, not a GEM. That is for newer Fords and controls more than just 4x4, it does everything that is not handled by a dedicated controller such as door locks, 4x4, windows, wipers, etc.

The ESOF module ain't programmable either. You're stuck with the code inside whether you like it or not...and I didn't like it. So I rebuilt a manual case and installed that instead. ESOF went in the trash/ to the scrapyard.

 

Great information. Thanks for the write-ups.

 

Better translation for the GEM is Get an Earlier Model; ie a vehicle without this infernal creation whose untimely failures bring a smile to Satan's face. We experienced just such a failure on our 96 Explorer one dark rainy night while driving home from South Bend, IN to the Ozarks. When wipers, interior lights, power windows and locks all failed I searched for the cause by swapping relays, fuses, and circuit breakers - all in vain. After spending the night in a hotel we drove the rest of the way home the following day in the light. Research (on this very site) unlocked the mystery and after obtaining a used replacement from a self-serve yard for far less than the several hundred dollar cost of a new unit my commitment to the older, simpler trucks was strengthened.

dn.

 

Well, the module pictured looks exactly like a transfer case shift module I have lying around that came from a 94 Explorer and I'm pretty sure I've come across service info that calls it a GEM module. Still prefer the manual shift version, seems everyone does.

I also have a GEM module from a 2008 Ranger that looks nothing like the Explorer device, yet it controls transfer case shifting along with many other functions and yes, it is programmable with the correct tools.

There seems to be a divide between the EECIV and the OBDII equipped vehicles, but the functions supported by these modules tend to be non emissions functions. Newer vehicles have these functions integrated with the ECM. Not a positive development in my opinion.

The whole GEM concept seems to be some sort of OEM black magic that Ford really does not want you to mess with. It's becoming a pretty controversial subject with the auto makers citing the Digital Millennium Copyright Act.

https://www.eff.org/deeplinks/2015/0...y-own-your-car

It does seem to conflict with other directives related to OBDII specific to allowing access to the repair industry and consumer.

On-board diagnostics - Wikipedia, the free encyclopedia

 

Yeah I don't buy anything that requires a trip to the dealer after replacing a module. And the less modules the better in my opinion. I work with control systems for a living so I ain't one of those guys that hate everything electronic, it's just that I prefer certain things not be electronically controlled. Transfer cases, door locks/windows, etc. Basically everything that a GEM runs. Lol.

Maybe they changed the name in later years, because that module is the same thing that was in my 88 Bronco II before GEM was even a thought in Ford's mind.

The OP's module looks the same as the one I ripped out of my 96 EEC-V OBDII truck... can't see Ford changing it so close to the end of the line but who knows. Lol. There is a divide but it's only in the engine/transmission controls. And I don't like the all-in-one theory either.

DMCA needed to die yesterday. If I BUY something then I should own it. I say all the source code for any given vehicle should be released to the public within a reasonable amount of time after that vehicle hits the market. If I don't like a feature then I should be able to compile my own build from source and download it to whatever module it's for. I would not mind paying a fair price to the manufacturer for any necessary software utilities or whatever might be required to enable this.

And yes I agree, manufacturers are trying to "black box" it as much as possible. Why do you think modern vehicles, most of which have at least one screen or LCD display and all of which have a serial bus installed for communications between modules, still only come with a Check Engine light? Don't tell me it didn't cross anyone's mind to replace that stupid engine light with a plain English fault description on one of the screens/displays... it's just that nobody will do it because then it's just that much easier for us to avoid a trip to the dealer.

Okay I'm ranting here... I'll shut my gator.