First off I want to say that I have searched the forums and still cannot figure it out. I want to start out by saying a few weeks ago I put it into 4wd and it had a little bit of trouble getting into 4wd but went in no problem after a few seconds. Fast forward to last thursday. Snowstorm here in connecticut. I try to put it into 4wd no go. Drove home at night in 2wd in the snow. I had the switch on 4wd the whole time. The next day go to work and still nothing. Then at night I am going over my friends and it pops into 4wd as I am going maybe 10mph. After that it stayed in 4wd and wouldn't come out. I put a 4wd electric motor in it thinking that was it. However that didn't fix anything. When the motor was out I manually moved the lever and put it back into 2wd so i could drive the truck as normal. Then comes sunday. Driving around in 2wd i try and put it in 4wd and it works flawlessly. Back and fourth between 2wd and 4wd its working as it should now. The next day(today) it is now stuck back in 2wd and will not shift into 4wd. I really don't know what it could be now. Maybe the module in the kick panel? A few things to note. The 4wd light on the dash only lights up when it actually works and goes into 4wd. If it doesn't go into 4wd when I move the switch then the dash won't light up. I only hear clicking in the passenger side kick panel when it works. If it doesn't work nothing happens on the dash and no noise. Any ideas on where to go from here?
Dan

 

im pretty sure there is a separate module for the 4wd system and they have been known to go bad. maybe its just the relay..

 

Yeah sounds like the module.

 

How can I test the module?