4x4 dead Please Help!

[msb454]

Hello all. I have an issue that is consuming my life and I need help. I recently bought a 2000 expedition 5.4 with the 4x4 not functioning, thinking I should be able to diagnose the issue easily. When I move the selector knob to 4h or 4l, absolutely nothing happens. I ohm'ed out the swith and it was all within spec. I tested for power at the shift motor and I am not getting anything. All fuses are good. When i start the vehicle, I get no 4x4 light, but I do get a Low Range indicator. Im thinking it may be the GEM module, but I an uncertain and dont want to throw money at it. Can anyone give some advice

 

[Bedrck47]

Do you have the prints for the 4X4 controls??

Where did you get the specs for the switch?

 

[Bedrck47]

Visual Inspection Chart
Mechanical
4WD mode switch

Electrical
Central junction box (CJB) Fuses 23 (10A), 15 (5A), 8 (5A), 6 (5A), and 20 (5A).
Battery junction box (BJB) Fuse 104 (30A).
Damaged wiring harness
Loose or corroded connector(s)
Circuitry
GEM

Check fuses using a meter check for voltage in and out of the fuse. Using a ohm meter may show that a fuse is good but using a volt meter proves that the fuse is good

 

[msb454]

Do you have the prints for the 4X4 controls??

Where did you get the specs for the switch?

I just found the specs for the switch online. Regarding the fuses, I just checked for continuity, not voltage. I will do that tomorrow. I do not have any prints for the 4x4 system.

 

[Bedrck47]

prints

 

[98EXPnSRQ]

I had a similar issue and the problem was the transfer case shift motor. There is a position sensor built into it and it went bad. I think when the pcm doesn't see the sensor it won't opperate the system.

 

[msb454]

I checked all fuses and they all show voltage going through them. I did go for a test drive for an unrelated repair with the transfer case motor unplugged and the 4x4 light was flashing which makes me think that it may not be the GEM. Are there any test procedures for the transfer case shift motor?

 

[Bedrck47]

Sent you a PM