Hi all
I have been in and out through the forum trying to decipher the problem with my 4WD not functioning. 2006 F150 S-Crew. Dash lights all light up when starting so those are functional however they do not light up when switch is activated. Checked the hub locking solenoid and have 12 vdc what seems constant to it with switch in any position. Removed vac tubes off solenoid and connected together and had vacuum at one wheel line. Did not check the other wheel. Checked fuses and all checked well. I will say I did not check every fuse marked 4x4 in the manual. May need another go at that. Replaced hub locking solenoid. Still not functional. Do not hear the solenoid coil picking up or any lights illuminating. Can anyone give further insight to this problem? Please dumb it down for a non-technical person here though. Thanks all.

 

If you do not hear a "clunck" like the transfer case is actually engaging then it's most likely a shift motor.

Check that the shift motor on the back of the transfer case is working. Crawl under the vehicle and lightly tap it with a hammer. Have a buddy try and shift from 2 to 4 wheel and see if that works. If it does then the shift motor is bad and needs to be replaced.

I just did this on my '05 and it fixed my issue of the lights not coming on when flipping the 4 wheel drive switch.

 

Take a rubber mallet or something and TAP the shift motor on the transfer case. You do not want to destroy it, just jar it.

Pull and check the connector at the shift motor. Clean it maybe, some dielectric grease won't hurt it.

You maybe already do it, but if not .... you should periodically shift it through all positions even if you don't drive it when you do so.

 

Thanks to you both. I will give that a go. I did further check the electrical system. It appears there is 12v constant at both transfer relays on the left fender wall. Both relays checked direct to battery and operate. Relay contacts close on coil energize so relays good. I did not think those relays should see 12v continuous. Next am going to tap the motor and check for 12v at the motor when switch moved to 4wd.

 

Perhaps your 4x4 actuators on the wheel are bad. I just had both of mine for bad, in my case it kept my hubs locked all the time. Perhaps yours went bad the opposite way?

 

I thought he said the indicator lights weren't lighting up .... they get no feedback from IWEs so they should light up even if IWEs fail ...
... or maybe I misread it?