Auto 4WD & 4x4 Not Working

[BrianDye]

Helping a buddy of mine, he picked up a 2006 XLT (4.0) pretty cheap at some kind of auction. Fairly problem free, except the 4x4 not working. It DID work when he bought it. Hasn't used it in a long time, went to go do some wheeling, and found out luckily beforehand, no more 4x4.

The auto will not engage (Only rear wheels spin), and neither high nor low will engage. When any button is pressed, nothing happens. No lights, no clicks, no noises at all. (Yes, vehicle is in neutral and brake pedal depressed when trying low)

I tried the good ol' knock on the transfer case motor with a mallet trick, but nothing happened. Any way to test the motor? I have a DMM and multiple test lights. I don't want to suggest him start replacing random stuff which would end up not being the issue. I remember reading that the control modules go bad fairly often, which is the little box under the glovebox, correct? Any way to test it?

 

[Bill MacLeod]

Check fuses in the under hood Power Distribution Box. My manual shows 2, 20 amp mini fuses for the 4 x 4 module. Fuse # 23 & 26.

The interior fuse panel has a 10 amp fuse #18 for the 4 x 4 module, 4 x 4 switch, reverse park aid, electrochromatic mirror, aux climate control, compass, heated seat switches.

 

[BrianDye]

Sorry, should've mentioned that was one of the first things we checked. Thanks for the suggestion though.

I also remember on MY '06, when any of those fuses were removed, I got the Wrench light on the dash.

 

[Jacob Linder]

Check for wire connections on the case itself, and for corrosion. I had some on mine when it wasn't engaging same issue, except mine would engage, but not go into low.