I'm Stumped! odd 4x4 behavior...

[OneEyedGimpyGuy]

Hello guys,
I'm stumped... I have a 2005 Ford Ranger 4.0L Auto with the (If I remember right) BW 1354 transfer case.
Problem is very intermittent. Works sometimes, sometimes it wont. When i switch into 4x4HI all the usual clicks are heard, the 4x4 light comes on for a few seconds, then shuts off... odd part is, there is still a chance its engaged after the light shuts off. I actually couldn't get it disengaged without moving back and forth last time. usually though, it isn't engaged. When it does stay on, 4x4 works flawlessly and doesn't have issues disengaging.
I have already done a complete fluid change (old stuff looked fine), checked all fuses for issues or corrosion, and swapped out the transfer case shift motor. I also took it to a stealership who charged me $80 to tell me its me not the truck and that sometimes, since the 4x4 isn't used all the time, it can get jammed....
Im stumped... The light never flashes and it comes on momentarily when the truck is turned on, and like I said before, when it works, it works... Any help would be much appreciated!

 

[OneEyedGimpyGuy]

Anything?

 

[Bronco638]

Sounds like the 4x4 control module might be starting to go.

 

[OneEyedGimpyGuy]

I just looked it up and I see a lot of diagnostics for older models. Do you know if its the same for an 05?

 

[Bronco638]

I'm sorry, I don't. I actually don't know much about the subject other than they tend to fail and when they do, most of the time it's the control module. My Edge has a used module in it after the original one failed. However, the p.o. did the swap. And, I don't know what the symptoms were that caused him to diagnose the module as being the issue in the first place.

 

[OneEyedGimpyGuy]

Gotcha I'll look more into it. The 4x4 worked all through the blizzard that just hit so that's good. But I think I was just lucky