never mind

 

Sounds like a problem with the shift motor. I'd check the connection and if its good tap the motor with a wrench while someone try's putting it in 4wd.

 

I tried tapping on shift motor, but wouldn't it need power to switch first? What feeds power to the switch? Is it the PCM, ECM or something else? The only other symptom & it may not be connected, is that when I'm going uphill & kick in passing gear it stalls like it ren out of gas & I have to let off & slowly give it gas to pick up speed. Don't know if it's connected but I noticed it about the same time 4wd went out.

 

Seen issues like this before with these trucks. Im not sure what the correct name is but there is a part that looks like a fork that acuates the 4x4 that could be bad. I think it is up front somewhere cant really remember. Or there is a vaccum leak. If im not mistaking these are run off of vaccum

 

Checked it, still nothing. Thanks for the suggestions anyway...

 

Check the GEM module for corrosion. It sits under the fuse block. It would not be a problem with the front diff engagement since you have no lights on the dash. With that it will be the GEM, shift motor, shift switch, or some other sensor that stops all activation of 4x4.

 

Thanks Kingfish51, do I have to remove fusebox to check GEM? BTW, I have already replaced Switch.

 

Yes, it is underneath. Might want to try a search, there may be more info.

EDIT - Just checked the owners manual. Fuses on the inside fuse block that MUST be good for 4x4 shift are 6, 15, 20, and 23. I believe they are all 5 amp fuses. Fuse that must be good in the under hood power distribution box is 17.

 

It's 99 degrees here, too hot to mess with as bad as I need it. I live on top of a big hill in the hills of northern Arkansas. Need my 4x4 bad!!!!
Does the GEM supply the power to the Switch?

 

I believe it is more of a controller. Also, see my edit above. Important.

 

Fuse #20 is dead, no fire whatsoever!! I read on another post somewhere that this was for manual trans only, what do you think? If I do need it, where do I look for the problem of no fire reaching it? What about using a jumper wire from batt to the fuse to see if 4wd works with power to fuse 20? Thanks for all your help!!!!!

 

Not an electrician, so no help on the jumper. There are others here that could help with that far better than I.
Per the owners manual (and if you do not have one, you can download one for free from http://www.motorcraftservice.com/vdi...&menuIndex1=13) inside fuse 20 is for Powertrain Control Module (PCM), Generic Electronic Module(GEM)/CentralTimer Module (CTM). So being it is for the PCM also, I can guarantee it is not just for a manual transmission.

 

OK, Thanks for the info! I'm tempted to run the jumper to get fire to fuse 20 but don't want to damage anything in the process. Anyone out there know if it would be okay to run a jumper? Also, does anyone know where Fuse #20 receives it's fire from?