Trouble shooting 4X4

I have a 2002 ford ranger XLT Super Cab 4x4 with 137,000 miles. It has the 4.0 SOHC with auto transmission.
The 4wd is not engaging when I turn the dash selector switch to either 4x4 High or 4x4 Low.
Also if any help when the truck is first started and the gauges and idiot lights go through their self checks, the 4wd lights do not come on at all.

When the dash switch is selected, there is no clunking indicating transfer case engagment or relay clicking inside the cab.

I have replaced the dash switch and checked all fuses but it doesnt help.

Any help would be greatly appreciated.

Turned out to be the transfercase control module located behind the passenger side kick panel for all those experiencing the same. Thats the culprit

Hi, we have a ford ranger it only has approx. 48,000 miles I have used the 4wd earlier this summer and have used in past winters, truck is never used for off roading, after a heavy snow went to get the truck out under the car port when I start truck up the dash lights show the fwd word and hi or low lit up after truck is started and regular lights all go off these do to and when I turn the on dash electronic switch to 4wd or 4wd hi all I hear is a clicking sound, it comes from under the glove box bottom, I checked it appears to be some vacume devise I pulled the end off and heard air leaking and put it back on, checked all the fuses they are o.K. Truck will not go into fwd at all. Truck is taken care of, never driven hard, etc. Never had this problem before. Really need to get this figured out as we are in bad mo. Weather now. Thanks for any help on this.

I don't know about the sound under the glove box but on the autmatic 4WDs there is a motor on the transfer case that when you take the lid off with a tamper-proof torque bit there are brass prongs inside that can get corroded ou just need to take a fine grained sand paper over them a few times and bend them out a little and all should be good.

This is a very slim chance what im about to say applies to you but if it does then that is good I dont know what the sound under the glove box would be but if you have lifted your truck since the last time you drove it in 4x4 anything over probly a 3in lift it wont go into for low and sometimes for high depending on the lift if you have a lift its an easy fix if you did

I cleaned my battery terminals today. My four wheel drive worked before I disconnected the battery and now it doesn't. It will not engage the four wheel drive. I checked the fusees and they are ok. I have tried to engage in: park, neutral, and in gear, nothing. Any ideas?

I have electronic 4 wheel drive, and when I try to engage the 4 wheel drive nothing happens. All the wiring, fuses, and linkage is fine. Any ideas?