Any Ford mechanics here

The earlier models operated on vacuum controlled by solenoids. Yours is probably the same. If they are making noise, won't engage/disengage etc there are several good troubleshooting videos on YouTube.
 
Exactly. I believe my front end are locked even in 2WD. I have vacuum going into the solenoid on the firewall. But with the car running in 2WD there wasn’t any vacuum being sent to the hubs. So I replaced the solenoid.

the problem I’m having is I’m getting intermittent vacuum coming out of the solenoid. Sometimes there is. Sometimes there isn’t. All while in 2WD. Is something wrong with the computer or shifter? I put my hand vac on both front hubs and both hold vacuum no problem. With the engine on in 2WD I jacked up the front end and spun each wheel by hand. And both from half shafts are turning. Should they be? I couldnt find any leaks in any of the vacuum lines.
 
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Exactly. I believe my front end are locked even in 2WD. I have vacuum going into the solenoid on the firewall. But with the car running in 2WD there wasn’t any vacuum being sent to the hubs. So I replaced the solenoid.

the problem I’m having is I’m getting intermittent vacuum coming out of the solenoid. Sometimes there is. Sometimes there isn’t. All while in 2WD. Is something wrong with the computer or shifter? I put my hand vac on both front hubs and both hold vacuum no problem. With the engine on in 2WD I jacked up the front end and spun each wheel by hand. And both from half shafts are turning. Should they be? I couldnt find any leaks in any of the vacuum lines.
The axle shafts should NOT be turning with the wheels in 2wd. I worked on one a few months ago and it finally turned out to be a faulty wiring harness after he took it to Ford specialist. The harness that goes under the carpet and comes out at the transfer case. All the switches etc worked fine but the relays etc weren't receiving the proper commands.
 
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That’s what I figured. There’s some kind of electrical issue. The vacuum system seems to be intact. I hate going to the dealer but this should be covered under drive train warranty I’m guessing
 
Do you have access to any wiring diagrams? Can you check connections at the 4wd switch and solenoid for corrosion, heat damage, or maybe even just a loose looking terminal in a plug. Do you have a multimeter and some back probes so you can hook it up to the solenoid and wiggle the harness and mess with the switch while everything is working?
 
The only wiring that I see related to the system is the plug that goes into the solenoid. I installed a new solenoid already and it didn’t remedy the problem. The wiring leaving the solenoid goes into a huge run of shrink tubing. Other than that I’m at a loss. The button to turn on my 4WD / 2WD is on my center console. There’s 4 push buttons there. Without cracking open that I don’t know how to get access to the back side of the switch

I do have a multimeter
 
Problems are usually not in the middle of a big harness. Its usually at a switch or plug, first place i would go is wiring diagram so I could check the wires on the switch. You are going to have to take it apart yourself or pay someone else to do it. You tube is your friend for getting unfamiliar plastic interiors apart without breaking stuff.
 
Lots of issues with the IWE solenoid. A quick YouTube search or Google will show you how to test it.
I put a brand new IWE solenoid in. And I still have the problem. The problem appears to be getting single to/from the solenoid. The plug for the solenoid appears clean with no corrosion. I have to figure out how to test the solenoid plug with a volt meter to see if the plug is transmitting to the solenoid properly
 
Exactly. I believe my front end are locked even in 2WD. I have vacuum going into the solenoid on the firewall. But with the car running in 2WD there wasn’t any vacuum being sent to the hubs. So I replaced the solenoid.

the problem I’m having is I’m getting intermittent vacuum coming out of the solenoid. Sometimes there is. Sometimes there isn’t. All while in 2WD. Is something wrong with the computer or shifter? I put my hand vac on both front hubs and both hold vacuum no problem. With the engine on in 2WD I jacked up the front end and spun each wheel by hand. And both from half shafts are turning. Should they be? I couldnt find any leaks in any of the vacuum lines.
I replaced my auto hubs with traditional manual lockers. The unit bearings on my F350 suck ass. I replaced it with Warne lockers and dynatrac bearing kit. Helps with gas mileage too since it becomes a true 2wd.
 
The IWE system sucks.

TSB 20-2028.

Personally after hundreds and hundreds of issues we "disable" the system with solid IWE's that are always 100% engaged. The transfer case is all that will be needed to engage 4x4.

people get alarmed at the thought of this until you explain that Dodge/ram vehicles haven't had hubs for ever (if ever), and no AWD vehicle I know of has any form of "axle disconnect".

When you put your Expedition in 4x4 Auto mode, the "hubs" are engaged all the time and if the ABS/traction control/4x4 computer detects wheel slippage the transfer case will be shifted to 4x4 in a fraction of a second.

solid IWE's will cost you a fraction of a MPG.
 
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Good luck with all this.....couldn't find a diagram of the vacuum system other than what's in the bulletins
 

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Just remembered this. If you remove the position switch from the dash and attempt to test it with an ohmmeter, it is NOT your std type switch. Each position will give a certain resistance reading like in the hundreds of ohms etc. I borrowed a Ford manual from one of the mechanics at my local dealer which gave me the different resistance values I should see, but I don't have that info anymore.
 
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