# Ford mechanic/super-genius needed



## glasswrongsize (Sep 15, 2015)

2003 F-250 Super Duty 4x4; 4x4 shift is a knob on the dash (2/4H/4L). It doesn't have auto hubs; "free" and "lock" hubs.

Knob in dash does no good; it remains in 2wd. The 4wd indicator doesn't illuminate in dash, (but the lights DO work as they light up at startup) and the xfer case does not engage 4wd.

I checked at the actuator with test light and have nothing there by moving switch. I jumped the signal wire(s) to ground at the bottom of the relay(s). I can shift to 4wd and back to 2wd by running the appropriate wire to ground (it locks the xfer case in as I can or can't turn front drive shaft appropriately). That ruled out bad relays or bad actuator in my mind.

When I jump the 4wd relay, the xfer case goes into 4wd, but the light still doesn't illuminate indicating that it did.

After monkeying (jumping relays and whatnot) with it and when I turn the ignition back on, I can hear the actuator clicking 3-4 times like a controller (or electronic logic of some sort) wants to make sure it is in 2wd?

I pulled the switch from the dash and I get a different resistance between different poles for each position...so it appears that the switch is OK.

I have checked the (5) fuses that are related to the 4wd and 4wd module.

I took the ole truck to town tonight and local (chain) auto parts store tried to see if there are any codes on computer but their reader would not "link". Went to another store and they could only reads codes if Check Engine light is/was on (so says the kid with hubcaps in his ears :huh: )

I have read that there is a controller behind the glove box, but I don't know which one it is, nor do I know how to test it. Any help would be appreciated.

Also curious what other sensors come into play to prevent a complete logic circuit? I know the brake switch and neutral switch come into play to go to 4L, but I don't think it matters in 4H (Shift on the fly). On the same note, I did check to brake an neutral switches; the brake lights DO work as does the neutral switch (I can start truck in neutral but not R or D, so the neutral switch does do its job).

I know there are a lot of good mechanics on here and I hope I gave enough info to diagnose or send me in the right diagnostic direction.

Thanks, Mark

PS, I tried looking into other forums for the answer and didn't find it; besides, we have as-good-if-not-better mechanics on this site as anywhere!


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## NewBerlinBaler (May 30, 2011)

Let's discuss the switch in more detail, Sounds like you checked it (or tried to) using an ohmmeter. You can't check a device "in circuit" with an ohmmeter so in order to perform a valid test, you need to completely remove all wiring from the switch. Is that what you did?

I have a 2002 F-350 with the Shift-On-The-Fly system and it sounds like you have the exact same rotary switch on the dash (2H 4H 4L) Never had mine apart as it's never given me any trouble but there should be a connector (or connectors) so the switch can be removed fairly easily.


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## r82230 (Mar 1, 2016)

Well you don't have an answer yet so here goes my best idea (so far).

Place blocks in front and back of both back tires. Slow walk towards the front of the vehicle, raise the hood (carefully). Inspect radiator cap for any possible defects, if no defect(s) noted proceed to option one (any defect noticed proceed to option two), Option one steps: jack up radiator cap, remove blocks from the back of wheels, push vehicle out from under said radiator cap. Roll new(er) vehicle under cap, block wheels, lower cap down, close hood completely (removing any empty or full adult beverage containers before closing), remove blocks from wheels, before attempting to operate (DO NOT operate, while consuming adult beverages either). Option two: steps are almost the same EXCEPT you would be using New's truck for the replacement vehicle, so you might want to do this quietly. :lol: :lol: :lol:

I am not endorsing either option as the best fix, BTW.

On the serious side, I will ask my son, who tinkers with a Ford truck about the same age (usually in my shed or yard, sometimes I need to remind him about putting tools back even). Don't get your hopes up very much, because usually he is always swapping parts in/out.

Larry


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## glasswrongsize (Sep 15, 2015)

NewBerlinBaler said:


> Let's discuss the switch in more detail, Sounds like you checked it (or tried to) using an ohmmeter. You can't check a device "in circuit" with an ohmmeter so in order to perform a valid test, you need to completely remove all wiring from the switch. Is that what you did?
> 
> I have a 2002 F-350 with the Shift-On-The-Fly system and it sounds like you have the exact same rotary switch on the dash (2H 4H 4L) Never had mine apart as it's never given me any trouble but there should be a connector (or connectors) so the switch can be removed fairly easily.


 I did indeed pull the dash so I could disconnect the switch to test it alone.

Update, I took to to a buddy's shop to hook him computerizer to it to see it (I hoped) it would point to a defective sensor, an open circuit or a grounded circuit; I didn't even have THAT good of luck...his reader (snap on) won't recognize the 4wd system AT ALL.

Decent friends with local junk yard...might start throwing parts at it till it works

...or wire around the computer. Grrrrr



r82230 said:


> Well you don't have an answer yet so here goes my best idea (so far).
> 
> Place blocks in front and back of both back tires. Slow walk towards the front of the vehicle, raise the hood (carefully). Inspect radiator cap for any possible defects, if no defect(s) noted proceed to option one (any defect noticed proceed to option two), Option one steps: jack up radiator cap, remove blocks from the back of wheels, push vehicle out from under said radiator cap. Roll new(er) vehicle under cap, block wheels, lower cap down, close hood completely (removing any empty or full adult beverage containers before closing), remove blocks from wheels, before attempting to operate (DO NOT operate, while consuming adult beverages either). Option two: steps are almost the same EXCEPT you would be using New's truck for the replacement vehicle, so you might want to do this quietly. :lol: :lol: :lol:
> 
> ...


Larry, I like your idea. Problem is, this truck is what I recently placed under my last radiator cap. Got rid of ol z71 with 386k miles. Had to hold in on the dash with one thumb while poking the 4wd button with another finger to get it to work...but it WORKED!!!

The dang thing sits high enough that the empty wobble-pop cans are helping me see into the engine compartment better. A few more cases, and I can sit in my lawn chair and stare into the engine compartment. Going to go in for a bowl of loudmouth stew (out of bottle instead of a can) and cipher on it s'more.

Mark

SOMETHING in the logic has it in some kind of "limp" mode I assume, as EVERY time I start the truck, I can hear the actuator cycle 3 or 4 times as the truck is making sure it IS in 2wd.


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## somedevildawg (Jun 20, 2011)

Glass I believe your best bet is on one of them other forums....those gear heads usually love to opin, I'm surprised they haven't sent you in the right direction.....I know your problem is getting the transfer case to engage although you may have a work around, are the hubs locking? They operate with vacuum I think, my 2001 does, not worth a damn anymore but I can still lock mine manually...
If I could get it to work by working around it, I probably would, but one of those ford mechanics that's been around a while should be of some help as they've seen the problem before.....if you don't have any luck let me know and I may be able to ask my buddy that's a service manager for a ford dealership, haven't talked to him in a while, need to touch base.....


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## glasswrongsize (Sep 15, 2015)

somedevildawg said:


> Glass I believe your best bet is on one of them other forums....those gear heads usually love to opin, I'm surprised they haven't sent you in the right direction.....I know your problem is getting the transfer case to engage although you may have a work around, are the hubs locking? They operate with vacuum I think, my 2001 does, not worth a damn anymore but I can still lock mine manually...
> If I could get it to work by working around it, I probably would, but one of those ford mechanics that's been around a while should be of some help as they've seen the problem before.....if you don't have any luck let me know and I may be able to ask my buddy that's a service manager for a ford dealership, haven't talked to him in a while, need to touch base.....


I have searched the other forums and have found lots of info/similar problems/same problems.

I do have a work around, but there is an awful glitch; it can go all the way to 4L while moving...even at, say, 55mph.

I don't have the vacuum hubs; mine are "lock" and "free". From reading the forums, even with the vac hubs, the xfer case will still engage, but the wheels won't pull. My xfer case won't engage (without working around it)

I ain't a member of any other forums and hoped that someone here knew the answer. I reckon I can go to the boneyard and take a whole heap of parts and replace stuff until it starts working.

Mark


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## somedevildawg (Jun 20, 2011)

Ya my transfer case will still engage I just have trouble remembering which way is locked and unlocked....they're not marked


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## pede58 (Oct 27, 2015)

Maybe I missed something but if your jumping the relays and it's working then isn't the relay bad? I just found out the other day that most standard code readers won't work on certain fords but I can't remember if a good scanner would work or if it has to be a dealer, didn't pay a whole lot of attention since I don't have a ford, most vehicles I know store codes for at least 50key cycles.


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## glasswrongsize (Sep 15, 2015)

pede58 said:


> Maybe I missed something but if your jumping the relays and it's working then isn't the relay bad? I just found out the other day that most standard code readers won't work on certain fords but I can't remember if a good scanner would work or if it has to be a dealer, didn't pay a whole lot of attention since I don't have a ford, most vehicles I know store codes for at least 50key cycles.


I'm jumping the signal side of the relay (sending it to ground) thereby activating the relay.

..you are correct, I am not actually "jumping" the relay. Poor choice of words on my part that would indicate the relay was bad.

Mark


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## SCtrailrider (May 1, 2016)

I'm not a ford person, but IF it's going into some sort of limp mode I THINK if you disconnect the battery's over night it will clear that code until what ever caused it triggers it again... maybe...


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## glasswrongsize (Sep 15, 2015)

SCtrailrider said:


> I'm not a ford person, but IF it's going into some sort of limp mode I THINK if you disconnect the battery's over night it will clear that code until what ever caused it triggers it again... maybe...


I didn't write ALL of the "diagnostics" (aka throwing stuff at it to see what sticks), but I did do that. Didn't work either. Thanks though. Going to try the 4wd control module tomorrow if I can get to it. Hauled hay today and resulted in two flat tires; one on the bale wagon and one on the gooseneck. Had spares for each. Blew hyd hose on skid steer unloading small squared; got all unloaded while hemorrhaging hyd fluid. Pulled accumulator out to change tires on it (going taller to account for higher stubble) and caught hyd hose on something and broke THAT hose too. Inniewho, taking a truckload of flat tires and two hyd hoses to town tomorrow and plan to visit the boneyard for a controller for the truck. Prolly bring tools and try it right there in parking lot. If that ain't it, may try the actuator...it actuates, but has other wires that presumably sense where it it in its cycle. 

Kinda like the ol' truck...first truck I've ever had that the AC works in  My dogs *REALLY * like it; they don't care if the 4wd drive works as long as the AC don't quit.

Mark


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## somedevildawg (Jun 20, 2011)

Damn it man....sounds like one of my days. I wouldn't worry to much about the going all the way to 4wd low mode.....just find that wire and run it to a switch that's hidden to break the circuit/make when you are for sure you want to got to 4L  (I once had an old ford that had none of the original ford switches from the Ignition all the way down.....) all toggles..... it was like being a fighter pilot


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## glasswrongsize (Sep 15, 2015)

somedevildawg said:


> Damn it man....sounds like one of my days. I wouldn't worry to much about the going all the way to 4wd low mode.....just find that wire and run it to a switch that's hidden to break the circuit/make when you are for sure you want to got to 4L  (I once had an old ford that had none of the original ford switches from the Ignition all the way down.....) all toggles.....  it was like being a fighter pilot


 It's the same wire; just make contact longer/again to go from 2 to 4L. It ain't something I would want to do "on the fly". May put one of them there "dooms day" switches in the dash... ya know the ones...with the red flappy thing over it.

I may also wire ejection seat while I'm at it....

Mark

....passenger's side  :lol:


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## slowzuki (Mar 8, 2011)

The controller on that 4wd if I recall is a simple thing that is not on the can bus so you can’t scan it. I’ve heard of several issues but the cheapest long term cure if keeping the truck, pull up carpet, take out the panel in the floor, unbolt the electric solenoid junk off the side of the t case and bolt one from a manual shift 4wd model onto the side. Voilà problem solved permanently and the shifter will always work.


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## glasswrongsize (Sep 15, 2015)

slowzuki said:


> The controller on that 4wd if I recall is a simple thing that is not on the can bus so you can't scan it.
> 
> That would explain that; thanks
> 
> ...


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## mlappin (Jun 25, 2009)

Google it, actually stay away from Google and DuckDuckGo it. Somewhere there is a forum dedicated to those trucks with at least one knowledgable person who has dealt with the same.

I had a issue with my Cummins and weird shifting, dealer had no clue, private shops had no clue, Cummins/Dodge forum said first to move the ground wire that runs behind the alternator, if that doesn't fix it then check alternator with an multimeter set on *AC. * It is possible to have a normally functioning alternator that has a leaky diode and that will show up as AC current. I can't remember the number, but it might have been as low as .05 volts AC would cause the power train module to do funky things, brand new alternators can do this as well.


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## slowzuki (Mar 8, 2011)

2003 wiring diagram

https://ww2-secure.justanswer.com/uploads/kennyz1963/2011-08-21_214040_2.jpg


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## glasswrongsize (Sep 15, 2015)

Update; I've seen SOOO many of this exact same questions on different forums and I could never find one with a final diagnosis... here goes:

The culprit turned out to be the actuator. The motor in the actuator still works(ed), but the switch/sensor inside the actuator that tells the actuator where it is located in its cycle was not reading the position of the actuator.

I thing the tell-tale is the fact that, I could activate the relays and make it work. Also, upon start-up, I could hear it cycling (to 2wd) 3 times. That was due to the fact that the GEM (computer) was actually good and acting upon the lack of signal as to where the actuator was positioned.

Hope this helps someone else in the future.

Thanks for all y'all's inputs

Mark


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## JD3430 (Jan 1, 2012)

glasswrongsize said:


> Update; I've seen SOOO many of this exact same questions on different forums and I could never find one with a final diagnosis... here goes:
> The culprit turned out to be the actuator. The motor in the actuator still works(ed), but the switch/sensor inside the actuator that tells the actuator where it is located in its cycle was not reading the position of the actuator.
> I thing the tell-tale is the fact that, I could activate the relays and make it work. Also, upon start-up, I could hear it cycling (to 2wd) 3 times. That was due to the fact that the GEM (computer) was actually good and acting upon the lack of signal as to where the actuator was positioned.
> Hope this helps someone else in the future.
> ...


Glad you got it fixed 
Nothing worse than a 4WD truck that don't have working 4WD!!!!
I have an 08 with the rotary knob and the vacuum hubs. I love not having to get out and lock the hubs, just turn the knob and go. My Z71 and my wife's Tahoe have the "auto 4WD" feature that supposubly locks the hubs when slippage is detected.


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