I'm not sure what else to try... I have a 2005 F-150... the 4x4 has not worked since about 6 months after I bought the vehicle. I have searched through these threads and nothing I have found yet has helped. No lights, no sounds, just nothing at all... BUT.... Every once in a while I will put it in 4x4 to see if it is working and twice it has worked.... but 90% of the time it does not... Could it be a short? could it be a loose connector? I would have taken it to the dealer when I first found out, but I was over my miles for the warranty... Any suggestions would greatly help...

 

I would check your fuses or connectors first. It is strange that you get no error codes or warning lights. Nothing! I am assuming that it is Electronic shift on the fly?

 

well, of course I have checked the fuses and that would not explain the random 2 times it has worked.... yes, it's a lariat with every option... so it just has the black switch to the right of the steering wheel.. I just do not want to pay out the butt for a tech to look at it for a couple hundred bucks... and have to be without a vehicle for a day... because no dealer around here will give you a loaner car.... Just kind of a pain, my truck is very well taken care of, not sure why the 4x4 isn't working.... and I am pretty mechanically inclined, I just haven't spend a whole bunch of time messing with it testing the electrical system to see if it's getting power, etc... just thought I might get an easy answer that may make my solution faster. Thanks... I will take any advice I can.... surely someone else has run into this problem.

 

I cut this out of the 2005 shop manual for Four Wheel Drive - Electronic Shift

Inspection and Verification

Visual Inspection Chart

Mechanical -------

Halfshafts
Integrated wheel ends (IWE)
Shift motor
Driveshaft and universal joints
Vacuum leaks
Fluid leaks
Matching tire sizes
Transfer case

Electrical -----

Junction box (JB) mini fuses:
11 (10A) (IWE vacuum solenoid)
20 (15A)
29 (15A)
Junction box (JB) fuse 111 (30A)
Wiring harness
Mode select switch (MSS)
Synchronization clutch
Connector(s)
IWE vacuum solenoid
Circuitry

 

Also this on operations.....
--------------------------------------

Electronic Shift

The Borg-Warner electronic shift transfer case is a 3-piece aluminium design. The unit transfers engine power from the transmission to the front and rear axles. Under normal driving conditions the unit is in 2-wheel drive high (2H), but when desired, the operator may shift into 4-wheel drive high (4H) or 4-wheel drive low (4L). The transfer case is shifted electronically. The unit is lubricated by a positive displacement fluid pump that channels fluid flow through holes in the rear output shaft.


Principles of Operation

The electronic shift on the fly (ESOF) system is an electronic shift system that allows the operator to choose between 2 different 4-wheel drive modes as well as 2-wheel drive. The operator can switch between 2WD and 4H mode at speeds up to 88 km/h (55 mph). To engage or disengage 4L range, the vehicle speed must be less than 5 km/h (3 mph), the brake pedal pressed and the transmission must be in NEUTRAL (or the clutch pedal pressed in manual transmission vehicles).

The transfer case is equipped with an electromagnetic clutch which is located inside the case. This clutch is used to synchronize the front driveline. When the mode select switch (MSS) on the instrument panel is turned, the 4x4 module (PCM) activates the electromagnetic clutch and powers the transfer case shift motor. When the shift motor reaches the desired position, as determined by the contact plate position inputs to the 4x4 module (PCM), power to the shift motor will be removed. When the transfer case front and rear output shafts are synchronized, the spring loaded lockup collar mechanically engages the mainshaft hub to the drive sprocket. Finally, the front axle integrated wheel ends (IWEs) are engaged and the electromagnetic clutch is deactivated.

Feature Inputs:
Mode select switch (MSS).
Wheel speeds (via CAN communication).
Contact plate position inputs A, B, C, D (grounded when closed, open circuit when open).
Transmission neutral.
Brake ON/OFF (BOO).
Feature Outputs:
Transfer case synchronization clutch.
Transfer case shift motor relays.
Integrated wheel-end (IWE) vacuum solenoid.
Cluster indicators (via CAN communication).
AWD mode (via CAN communication to PCM).
Integrated Wheel End (IWE) System

The integrated wheel end (IWE) system contains the following:

Vacuum reservoir
IWE solenoid
IWEs (spring loaded vacuum hubs)
Vacuum hoses
Check valve
The IWE system uses vacuum hubs that engage the front wheel hubs to the front halfshafts or disengage the front wheel hubs from the front halfshafts.

The IWE solenoid receives engine vacuum from the vacuum reservoir.

When the 4-wheel drive system is in 2WD mode, the 4x4 module (PCM) supplies a ground path to the IWE solenoid to apply vacuum to the integrated wheel ends (disengaging the front hubs from the front halfshafts). In 4WD mode, the 4x4 module (PCM) does not supply the ground path to the IWE solenoid, vacuum is not applied to the integrated wheel ends and an internal spring keeps the front hubs engaged to the front halfshafts.

 

lots of info there... I will have to go through it and see if I can trace any of this down... wish it wasn't pouring rain right now.... Thanks....

 

you may want to look at the front diff. it has a vacum.

 

The front diff is not locked and unlocked any more like the 97-03. All locking of the front are done at the IWE's (hubs) on the 04 up. These have a default (no vacuum) of locked. He needs to find out if it is the transfer case which is shifting first.

 

I have a problem with my 2005 F-150 with 28,000 miles. The 4 wheel drive was grinding and stopped engaging. So I took it into Ford and they replaced the Vaccum Control Switch and the Left front Hub assembly. Now it is engaging but I am having a problem with it dis-engaging. It takes several minutes for it to dis-engage. So I took it back to Ford and they are telling me that because the tires circumfrence is small on the front than the rear due to tire wear. It is binding up the 4 wheel. Does this even make sence? Any ideas would be muc appreciated.

 

Did any of this fix your problem? I also have an '05 Lariat 4x4 and mine used to work. When I would put it in 4hi I would hear a clunk and the light would come on, now I tried it and no clunk and no light. I think its not engaging.
Truck only has 25k miles on it.....

 

My problem was fixed by putting two new tires on it. That is the weirdest thing I have ever seen.

 

There are issues with the 4x4 system I.w.e ends ingesting moisture/water into vacuum actuation system causing no 4x4 or ratcheting outboard I.w.e ends. (Even if you don't go 4x4'n ) pull off vacuum hoses @ I.w.e ends and check for moisture/water/rust also the I.w.e is not part of the wheel bearing itself It is the part on the axle side (inboard) of the spindle. (EVEN DEALERS CAT LISTED WRONG )Many shops just replace the wheel bearing side this may fix the symptom but not the true cause of damaged I.w.e. ! Check with a reputable dealer they should have info on this condition and repair procedure.

 

Hi,I'm new here If I'm doing this wrong let me know.I can't find how to post my question.
I bought a 1998 F 150 last year & recently found out the 4 WD won't engage.
It did shift to low but no 4 WD & it won't shift out of low.
It has a switch on dash to engage 4 WD.
When I start the truck the light flashes 4 WD low then goes out.
It's in low but no 4 WD & it won't shift out of low.
I remember hearing a noise in dash before by the glove box. Did'nt I read somewhere that there's a control there that helps to engage 4 WD?
The switch tested ok. I took the transfer shift motor apart. It looks new like seller said it was & it seems ok.I feel that the problem is between the switch & the transfer shift motor.
Thanks for your help,TDV

 

It seems like this is a defect. I have a 2005 F150 also. Ford should issue a recall, rather than have consumers pay for the repair. Who do we write to?

 

I Did a little google search with my issue and it brought me back home.. Haven't been on here in a while.

So I have almost the same issue, I have to bet it is the Integrated wheel-end (IWE) vacuum solenoid.

A week ago I heard a a felt a grinding noise in my front end and pulled over thinking I drove over something and it was dragging under me. I have not used my 4 wheel drive system since last winter so never imagined it could be that. My mechanic was getting the truck the next day so I ask to check to see it something was wrong with my brakes. He reported back all was fine with my brakes and the issues was gone. & it was no more grinding.

Last week I helped a friend and had to use 4 wheel drive to get into his driveway. No problem locked in and drove great! When I went to take it out of 4 wheel the grinding came back, so I stopped put the truck in nuetral and flipped the switch to 4WH then back to 2WD and the issue went away for about 2 miles. I went through this sequence about 5 times & it finally went away until today driving to lunch only now the grinding is louder so I am going to the dealership ASAP and pay the high hourly rates. Damn warrenty is long gone with 62000 miles...

Any idea what the repair was to get the vacuum solenoid repaired and replaced? Any way this is something a semi mechanical person could do on their own??