Hi Guys!

I'm having the weirdest issue with my truck, since I own it, and I'm sure some of you know, that I went through basically all the problems, you can name with these trucks.
The story might be a little long, but it feels like it's necessary to tell, so there is a full picture what I'm dealing with.
I used to have the AE software, but one night someone decided to brake into my truck, and stupid me left the laptop and the AutoEnginuity data cable in it - so that's long gone. But I remember having a DTC - don't remember the # - says "2WD solenoid problem".
And now the story :
heading to Alabama - about 400miles from home - on the highway my truck "jumped" into 4WD hi , with the switch ( ****) in 2WD position. Pulled over, wiggle the switch, turn to 4WD , back to 2WD, nothing. So I turned all the way to 4WD low, and it jumped into 4WD low, and just stuck there. I'm on the side of the highway, absolutely no tools at all, 60mph traffic, and I can only do about 25 WOT. Well, I managed to limp into a town, and found a dealership. Checked the truck right away, turns out the 4wd motor is bad, and they don't have it in stock. No problem, the tech was nice enough to remove the "thing", and I was on my way again, with the 4wd motor on the cab-floor.
Got home, ordered a new one, it arrived, and I installed it. Great! - I thought. Just in case I turned the ****, goes into 4WD , then into 4WD low, and it stayed there again!!! WTF? pulled the motor , and tested it on the bench, it turns both ways like a dream. OK, lets go to the parts store, and replace the relays. Same issue.
Pulled the switch, test it, measure the resistance, and even though I'm not sure what the resistance should be, it seemed like it's working, I always got the same resistance in each stage.
Checked the voltage under the truck at the connector, and nothing . Zero.
So, I checked the relay connections, and I get a solid 12V at one of them - on the trigger circuit side-, and I get 2.8V on the other one. ??? And no matter what I do - turn the switch, wiggle the connectors, even disconnect the PCM, these numbers just stays like this.
Now tell me, that it's not a ghost in the machine.
At this point, I have a feeling, that the answer lies between the switch and the relay housings, but I have no idea what's between these two. Is it the PCM, is it just wires, or is it something else?
So my question is: is there anybody, who might have a wiring diagram of this 4WD circuit? I tried to follow up the wires, but it's just impossible...

Thank you guys in advance!

 

I bumped you to SuperDuty so the guys here can see it and hopefully solve your problem. In the meantime, quite playing with the switch...

 

I've attached two electrical diagrams. They are for a 2004, but I believe a 2003 should be pretty much the same. The first one is input to the 4WD control module, the second one is outputs from the 4WD control module.

The shift motor cannot activate itself. So the dealer that said it was bad was wrong. The only way I can see the shift motor activating without a command from the 4WD control module would be a serious relay failure, and I just don't see that happening.

My assumption would be a bad 4WD control module.

FYI, though. These diagrams are for a 2004. Somewhere prior to 2004, the 4WD module didn't exist and these functions were controlled by the GEM module. I THINK the 2003 had the 4WD control module, but I'm not entirely certain. If you decide the module is the problem, you'll have to determine for sure which one you have.

 

Thanks for your really helpful reply!
Yes, usually I have to do parts search as it's an 04 truck, the 03 year somehow doesn't show the 6.0.
You're right, I'm sure it has to do something with the 4wd module. Would you be able to tell me where is it located exactly?
Thanks.

 

It's behind the glove box. Open the glove box, push in on the sides and the glove box will open all the way down. You should see the module back there somewhere.

 

Also. The module requires programming. The service manual says the service department should save the module programming and download it into the new module. I think they can program it from scratch, just based on your vehicle information now.

If you buy one and replace it, you might have to take it to Ford to be programmed.

 

I really appreciate your help!
Thank You!

 

I asked the dealer, and they can get me a module for about $160, what's not a bad price, and just like you said, it requires programming by them.
Now, since I hate to let anybody - especially the Sarasota Ford dealership - touch my truck, I'd like to make sure that it's not just the switch.
I checked the resistance , and here is what I've got
2WD - 3900 ohm
4WD - 1100 ohm
4 LO - 360 ohm

Does this sound right?

 

Interesting.

My service manual says it should be 619 Ohms for 2H, 270 Ohms for 4H and 130 Ohms for 4L.

I took my switch out and checked it and I get what you get.

 

Huh!

Well, I removed the 4X4 module anyways, took it apart, and on the backside of the circuit board, where the soldered connections are - several of them looks bad. I mean there is some serious discoloration at two spots, and that contains several "legs". I cleaned them up, re-soldered it - but still 2 of them looks like that the conductive surface is damaged. Put it back in, and nothing changed, so it sure looks like it will be a new module installed soon.

Thank you for going through some hoops for helping me!

 

Did you get it fixed? Was it the module?