Ok I have been trying to solve this problem through searching threads instead of asking "another Esof question". My transfercase will not shift, did the first test by cheking for cycling at the 2 pin connector. Thought I had it but not consistant. Checked relays. Now to clarify I am working on an Excursion but also have a F250. I swapped relays from my working truck to my Ex, truck continued to work Ex didn't. So I got another shift motor used that does bench test ok, atleast the motor works. So now I have checked all fuses by continuity and voltage all pass. Now I have no power at my switch. Pulled fuse block out and check the back all looked ok. BTW the windshield leaks and haven't gotten it fixed yet. Took connector off the back of fuse block found the correct wire(I think) and checked for resistance ohms meter reads 73 ohms and continuity test falls(won't beep). According to the diagrams I've found here there is not another connector between the fuse block and the 4x4 switch. Please help I am at a loss.

 

Well while waiting took out module behind the glove box and opened it up to find corrosion and burnt spots. So does the switch get power through the module , cuz the diagram i saw didn't look like it.

 

Hey Fuelman!

Lemme get that schematic up and take a look. By the switch, you mean the one one the dash, right?

 

You have an 02 and an 03, right? One of the other guys in the ESOF Inop thread said the schematic is the same.

Looking at the 03 schematic, the dash switch gets power from the module behind the glovebox. It should have power on pin 3 (the White wire with a light blue stripe) and the switch sends it through a resistor (different for each position - off, lo, hi) and returns on the dark blue wire of pin 2. The module must sense current associated with each switch position.

 

By the way, the backlight for the switch does not get power thru the module behind the glovebox.

 

Also, on pin 3, you may find the voltage is only 5 V. It is labeled reference voltage, which on many computer circuits is just 5V, vs the 12 that we are used to in automotive stuff. I'm not sure which one it is, so check it with a voltmeter, not a test light.

 

SC thanks yes switch on dash. So first I need to get a new module cuz this one is wacked from a leaky windshield. So will have to get that done first b4 any other testing. Any idea on part #s or cost and is it a dealer item only??

 

No idea - I would check eBay and junkyards. Ask hookedondiesel from the other thread - I think he was shopping for one also.

 

Found one on Ebay checking compatibility for 189w/shipping new in box. numbers look the same except the first 4 digits.

 

These (GEM) modules are "truck" specific.
Meaning, they control qiute a few things, power windows, lock, etc, etc.
Keep this in mind, "your" module contains the "software' for "your" truck, if the one you purchased, doesn't completely work, as in, "now your windows don't work" you'll have to download the software from your old module to the new one. This is done through the OBD port,
Your old module will have to be re-installed to do this,"if the new one needs an update".
Also, I'm still in the process of checking my problems, cold weather, no garage to speak of etc, etc, has put this on the back burner for now, for me.
BUT, I did learn that, in testing your motor connections, (the two plugs to the transfer-case motor for the 4x4) you need a load on them, a tech suggested, to use a headlight, wired to the two prongs.
This will put the required "load" and if the light, lights up, (for a couple of seconds only and pulse's) the circuit is good and your motor is defective.
A meter, (Digital Volt meter) will NOT pick up these pulses, it doesn't have time to "catch" them.
Your situation does sound like it's the module behind the glove box.

fuelman, I have a question, does the module on your 250 behind the glove box have a center plug missing on it. No center plug but only on both ends?

 

Great info in this thread, please be sure to keep us updated when you find a solution.

 

Yes the center connector space is open.

I think the modules are the same. The description says it works om all 03 models Excusion and Superduty with all trim and engine. Considering that there seem to be no changes in trim between a 02 Ex limited and 03 i think it would work. The number on the original module is 2C3T-14B205-AA and the ebay is 3C3Z-14B205-AA Now the one in my F250 Kingranch is 3C3T-14B205-AB. Can anyone explain the prefix difference?

 

Thats the exact same number as mine.
I wish I could explain the diff...
All I know is mine is the F250 xlt.
Thanks for the info on the empty space.

Is this the part, it does say it matches on this one....
http://www.ebay.ca/itm/NEW-OEM-MULTI...-/400336502283

 

Sorry, i just noticed you have a "Z" on your ebay part, something to think about.

 

Checked with the Ford dealer and the new number is the same as Ebay one. I tried to copy the link but don't have much luck doing that,so here is the Item #230837955915. The original part number updated to the 3C3Z-14B205-AA. The parts guy said most of these are direct "bolt in" as replacements now. He did say on RARE occassions you have to go in a "reprogram" a certain area but he said he has only had to do that a few times. So the original 2C3T-14B205-AA is replaced by 3C3Z-14B205-AA. He also said the 4 digit prefix is year and production stamping but the 14B205 is the equipment matching.