2001 f250 4x4 will not engage, no 4x4 dash light, hear no clicking at IWE solenoid, should there be power at 3 prong connector at IWE solenoid

Visual Inspection Chart Mechanical Electrical

• Half shafts
• Integrated wheel-ends (IWEs)
• Shift lever and/or linkage
• Driveshaft and universal joints
• Vacuum leaks
• Fluid leaks
• Matching tire sizes
• Transfer case

• Central junction box (CJB) mini fuses:
  • 11 (10A) (IWE vacuum solenoid)
  • 28 (5A)
  • 29 (15A)
  • 30 (15A)
• CJB fuse 111 (20A)
• Wiring harness
• Mode indication switch (MIS)
• Synchronization clutch
• Connector(s)
• Integrated wheel-end (IWE) vacuum solenoid
• Circuitry

Is the system ESOF ( Electronic Shift On the Fly ) or MSOF ( Mechanical Shift On the Fly ) ?

Operationally vacuum holds the IWE ( Integrated Wheel Ends ) out, and once vac is removed the spring engages the IWE.

Lift and support the front of the truck so the front wheels are off the ground ( take safety precautions, chock wheels, jack stands, etc )
Key on, engage 4x4 and try to turn the front drive shaft.
If it turns it is a problem with the transfer case.
If it doesn't it is a front axle engagement problem.

- If the front drive shaft does not turn :
Shut of the truck ( still jacked up, and supported ) remove the vac lines from the IWE. The spring should push the gears in, without the vac line on.
Check the vent line ( tube that is routed into the engine compartment with nothing attached to it ), for blockages.
If the vent line is clear, and with the vac lines off the IWE should be engaged ( both front wheels locked ).
If they lock, the problem is with the IWE solenoid not shutting off vacuum to the IWEs. There is a TSB on the 2004-2006 IWE solenoids, a newer revision has been made, and used from 2007 and newer MYs.

Here is a block diagram of the IWE system


If the indicator light on the cluster is illuminating, I would suspect that the transfer case is fine ( shift motor plates are making contact, singalling that the shift happened with the indicator on the cluster ), so when you jack up and test, look towards the vacuum lines & IWE solenoid.

Operationally vacuum holds the IWE ( Integrated Wheel Ends ) out, and once vac is removed the spring engages the IWE.

Lift and support the front of the truck so the front wheels are off the ground ( take safety precautions, chock wheels, jack stands, etc )
Key on, engage 4x4 and try to turn the front drive shaft.
If it turns it is a problem with the transfer case.
If it doesn't it is a front axle engagement problem.

- If the front drive shaft does not turn :
Shut of the truck ( still jacked up, and supported ) remove the vac lines from the IWE. The spring should push the gears in, without the vac line on.
Check the vent line ( tube that is routed into the engine compartment with nothing attached to it ), for blockages.
If the vent line is clear, and with the vac lines off the IWE should be engaged ( both front wheels locked ).
If they lock, the problem is with the IWE solenoid not shutting off vacuum to the IWEs. There is a TSB on the 2004-2006 IWE solenoids, a newer revision has been made, and used from 2007 and newer MYs.

Here is a block diagram of the IWE system


If the front drive shaft turns, it is either the connector to the transfer case or the transfer shift motor not functioning correctly.
Check the connector for corrosion on both the male and female pins.
Turn key to run ( do not start ) and have someone turn from 2WD to 4H and back again while hitting the transfer case with a dead blow hammer ( not a steel hammer ) to see if the shift motor is hanging up.

Not sure if selector does not engage 4x4 hi or 4x4 low means the lights on the mode selector switch do not change, or if the switch selects 4H, but the front wheels do not function, so hard to provide a true direction on where the problem could be.

Sounds like an issue with the IWE ( Integrated Wheel End ) solenoid. There is a TSB where the IWE solenoid can ingest water, which will cause the front axle to lock into place.

http://my.voyager.net/~sscully/file_tsb06_08_15.pdf

I am going to take an assumption that this is an extension ( even though the opposite problem ) with the 1st revision of the IWE solenoid without the splash plate.

Take a read of the TSB, and check the IWE solenoid both dry and wet to see if it is not operating the vacuum valve ( turning off vacuum to the hubs to allow the spring to close the IWE ).

The only other thing I can see is an issue with the lube in the IWE spring holding up when it is wet. That is a bigger SWAG than the above statements, but not completely unfounded.

this is caused by a defective starter solenoid, the heavy contact that engage the starter get burned the solenoid engages (the click u hear) but the starter gets no power due to the contacts being burned away

Is the system ESOF ( Electronic Shift On the Fly ) or MSOF ( Mechanical Shift On the Fly ) ?

Operationally vacuum holds the IWE ( Integrated Wheel Ends ) out, and once vac is removed the spring engages the IWE.

Lift and support the front of the truck so the front wheels are off the ground ( take safety precautions, chock wheels, jack stands, etc )
Key on, engage 4x4 and try to turn the front drive shaft.
If it turns it is a problem with the transfer case. Check the fuse for the shift motor ( if ESOF ) & the connector to the transfer case ( some get gummed up with oil & road dirt ) that the pins are clean, and making contact.
If it doesn't it is a front axle engagement problem.

- If the front drive shaft does not turn :
Shut of the truck ( still jacked up, and supported ) remove the vac lines from the IWE. The spring should push the gears in, without the vac line on.
Check the vent line ( tube that is routed into the engine compartment with nothing attached to it ), for blockages.
If the vent line is clear, and with the vac lines off the IWE should be engaged ( both front wheels locked ).
If they lock, the problem is with the IWE solenoid not shutting off vacuum to the IWEs. There is a TSB on the 2004-2006 IWE solenoids, a newer revision has been made, and used from 2007 and newer MYs.

Here is a block diagram of the IWE system

Sounds like the IWE ( Integrated Wheel End ) did not lock in for some reason.

Could be the IWE solenoid did not shut off the vacuum to the wheel ( usually the solenoid problem is the other way around ).

Could be the vent tube from the IWE into the engine compartment is plugged.

Also could be a problem with the transfer case.

Is the system ESOF ( Electronic Shift On the Fly ) or MSOF ( Mechanical Shift On the Fly ) ?

Operationally vacuum holds the IWE ( Integrated Wheel Ends ) out, and once vac is removed the spring engages the IWE.

Lift and support the front of the truck so the front wheels are off the ground ( take safety precautions, chock wheels, jack stands, etc )
Key on, engage 4x4 and try to turn the front drive shaft.
If it turns it is a problem with the transfer case.
If it doesn't it is a front axle engagement problem.

- If the front drive shaft does not turn :
Shut of the truck ( still jacked up, and supported ) remove the vac lines from the IWE. The spring should push the gears in, without the vac line on.
Check the vent line ( tube that is routed into the engine compartment with nothing attached to it ), for blockages.
If the vent line is clear, and with the vac lines off the IWE should be engaged ( both front wheels locked ).
If they lock, the problem is with the IWE solenoid not shutting off vacuum to the IWEs. There is a TSB on the 2004-2006 IWE solenoids, a newer revision has been made, and used from 2007 and newer MYs.

Here is a block diagram of the IWE system


Start with the lifting and supporting the front of the truck to check the front drive shaft when 4H or 4L is engaged to know which way to look.

Some times the connector on the transfer case for the ESOF version can be corroded and just needs to be cleaned.

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.
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.
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.
Good luck and start with checking the IWE system in the front end.

You can check to see if you have a problem with the IWE ( Integrated Wheel End ) solenoid.

Operationally vacuum holds the IWE ( Integrated Wheel Ends ) out, and once vac is removed the spring engages the IWE. The IWE solenoid is what is to turn off the vacuum.

This is a block diagram of the IWE vacuum system


A quick test is to pull the vacuum lines ( not the vent lines ) from the IWE and plug them. This should remove the vacuum from the IWE, and they should engage ( at all times, pushing a dead axle ). If you shift into 4WD ( H or L ) it should work. This is a quick test that might not tell too much if the issue is with the IWE themselves.
Are you sure the problem is with the wheel locks ? Could be a transfer case issue.

Lift and support the front of the truck so the front wheels are off the ground ( take safety precautions, chock wheels, jack stands, etc )
Key on, engage 4x4 and try to turn the front drive shaft.
If it turns it is a problem with the transfer case.
If it doesn't it is a front axle engagement problem.

Is the system ESOF ( Electronic Shift On the Fly ) or MSOF ( Mechanical Shift On the Fly ) ?

Sorry, brain fade this AM, posed clarification, not a solution ( no picture )

It could be the IWE ( integrated Wheel Ends ) or the IWE solenoid not allowing the IWEs to engage. Might want to check ( at a minimum ) the IWE solenoid to the IWE, and the vent from the IWE ( to make sure it is clear of obstructions ).
This is the block diagram of the IWE vac system

Vac is applied at the IWE to keep them disengaged. When VAC is removed, the spring in the IWE should push the gears together and lock in the front wheels to the axle. There was a 2004-2006 TSB on a faulty IWE solenoid that could intake water, and allows water to flow to the IWEs, causing problems. Keep that one in the back of your mind as you look for problems.
Link to a PDF copy of the TSB
http://my.voyager.net/~sscully/file_tsb06_08_15.pdf