2005 4x4 High light blinking / no auto [Solved]

[ImpactF0nt]

Sorry for this paragraph but I really thought I'd add as much context as possible, since I really need help with this since I can't figure out whats happening.

I've got an 05 4.0 with advancetrac 4x4 with 150,000 miles... about a year ago to date, I had the transmission completely rebuilt by a HIGHLY reputable repair shop after it went out with the light show a few months prior. They did an amazing job with it, told me they built it with a problem solving kit as well, and the thing now shifts better than my parents 17 edge! But, literally right after I got the vehicle back, the 4x4 High light issue started on the lot, not shifting or anything, it wasn't an issue before. It's only the 4x4 light, adv trac is working, no warnings, no ABS light, just 4x4 high blinking.
So fast-forward to me ignoring it for another year, I finally decided to do something about it, since I had to do my front suspension anyways, so I ordered and installed new moog struts and swaybar links (it was a ***** getting the bolts off), and installed a brand new 4x4 shift motor to the t-case and changed the fluid. Of course I test drove it and the problems continued with the 4x4 light flash so I parked it and, after hearing from many that it was a grounding pin issue, relocated the grounding pin to another place (it was originally in its intended place but I figured i'd try), and that of course didn't help as the issue persisted. I tried once more to ID the problem by disconnecting the connector altogether to see what happened, and the 4x4 light came on immediately flashing this time, so I knew of course the motor was being registered by the computer.

The thing WILL shift into High, albeit it will only do it briefly after starting the car, then it will lock out again which I really can't stand so leaving it alone isnt an option for me. It will always shift into Low for whatever reason no matter how long i've driven. So I know now this isn't an issue with the shift motor itself...

So after this I heard it could also be a 4x4 control module issue, so I checked real quick to see mine in person, but upon opening the glove box, the space where the module USUALLY is was blank.. so I had assumed this had something to do with the AdvanceTrac RSC system equipped on my vehicle, since I hear that was an 05 exclusive. I couldn't find anywhere anything about where it could be if it is present at all. Anyways I need to know what I should do, should I locate the module and replace it? Is it even individual anymore or is it bundled inside another computer module now?

I'm really at a loss here, again sorry for the essay but I'm getting desperate to fix this stupid thing already. Anyway, any information is appreciated.

 

[Mbrooks420]

Get the codes read.

 

[ImpactF0nt]

Get the codes read.

Did that already, no codes.

 

[Mbrooks420]

If the lights are blinking, there are stored codes.

 

[ImpactF0nt]

If the lights are blinking, there are stored codes.

I am really not getting codes, just scanned again.

 

[ImpactF0nt]

Could it be that i need to move the ground to the frame of the vehicle?

 

[Mbrooks420]

Your scanner probably doesn’t read ABS and body module codes.

 

[ImpactF0nt]

Your scanner probably doesn’t read ABS and body module codes.

That's what I'm thinking, I did go to autozone to get a second opinion from their scan tool but once again it picked up nothing. The only other thing I can think of doing at this point to retrieve the code is to go to the dealership, not sure if they'll do that for free I'm assuming they won't. I'm obviously not gonna buy a pro-grade scan tool for this though.

 

[Mbrooks420]

I think it’s standard for Ford to charge a diagnostic fee. You could probably check this with FORScan.

 

[drdoom]

I believe the 2005 models have the 4x4 control module integrated into the main ECU. As Mbrooks420 stated, you need to get on a pro level scanner. AutoZone free scans won't read it.

 

[drdoom]

That's what I'm thinking, I did go to autozone to get a second opinion from their scan tool but once again it picked up nothing. The only other thing I can think of doing at this point to retrieve the code is to go to the dealership, not sure if they'll do that for free I'm assuming they won't. I'm obviously not gonna buy a pro-grade scan tool for this though.

I believe I paid about $70 USD for a high quality USB interface cable for use with the ForScan open source software. Very useful for diagnostics.

 

[ImpactF0nt]

I believe I paid about $70 USD for a high quality USB interface cable for use with the ForScan open source software. Very useful for diagnostics.

I have heard of forscan being used on some of the newer Fords, I didn't even know it worked with our older ones. So are you saying I can get all of these niche hidden codes, and other abnormal diagnostic features by using it?

 

[drdoom]

I have heard of forscan being used on some of the newer Fords, I didn't even know it worked with our older ones. So are you saying I can get all of these niche hidden codes, and other abnormal diagnostic features by using it?

Correct. Live data, codes, and self tests.

 

[SyberTiger]

Have you considered that one of the wheel speed sensors is not reporting correctly?

How many miles are on the wheel bearings?

Check the slop on the wheels one at a time by jacking up each wheel and doing the 12-6 o'clock and 9-3 o'clock slop test to check if wheel bearings are worn.

 

[ImpactF0nt]

Alright good news, I know I haven't acknowledged some of the replies yet. I fixed the problem.

I went out and disconnected the battery, (I had already done this before but only for about 4 minutes).
While the battery was disconnected, I got a self-taping screw and a washer, disconnected the ground pin on the shift motor, and remounted it a second time directly to the crossmember of the frame right next to it, so now the ground is directly connected to the frame.
After that was done about 25 minutes had elapsed since i disconnected the battery, (with the headlight switch on for good measure).
Upon taking it for a ride I immediately felt the 4x4 Auto was functioning again around tight turns like the cul de sac in my subdivision, which hadn't happened in years. I drove for about 10 miles and 20 minutes and all the while, no problems, 4x4 Auto was working, 4x4 High was able to shift and Low range as well. Tested with AdvanceTrac off (which would normally cause wheelspin while it was broken), Auto took care of that as well.

So yeah, whatever I did there fixed it, unfortunately I'm unsure which thing actually caused the fix but bolting ground to frame does work, as you can see. I'm guessing if that did not end up fixing it, I would say replace the ECU or PCM if its separate idk. If this is happening to you still in your 05 or whatever, try disconnecting the battery for more than 20 minutes or connecting ground to frame directly!

Thanks everyone for your responses still, I appreciate the willingness to share what you know and help out, hope this thread helps someone else soon!

Edit: I'll provide an update if the system takes a dump on me again within the next few weeks, but it seems to be functioning just fine now.