2002 Ford Explorer XLT wont go into 4x4

I have a 2002 ford explorer xlt, the 4x4 module box was gone. I replaced it and now it still won't go into 4x4. Any help as to why? sorry no indicator light on either as to what it is in, 4x4 auto- 4 low-4high none showing.
Any help appreciated.

what engine and what is the production date of your truck? 4.0 or 4.6, with or without traction control? there is a early and a late version for wiring.

with no lights on I would be checking fuses, and where did you get the module from? is it a known good unit?

it was late 2001 (booked as a 2002), has 4.0 has traction control also not working. Fuses all checked and good. I bought it at a wrecking yard, was told it worked.

the lights for the 4wd start from the 4wd module so you should verify that you have the correct starting point. there are two plug in's for the module. one should have the #1 pin a black and white wire that should have battery voltage all the time. the #2 in that connector should be a white wire and that too should have power all the time. #7 a black wire should be ground. #9 a violet and orange wire should be battery voltage in run or acc. #10 an orange wire should be power in start.

you should unplug the module and check the pins in the wire harness for these power and grounds.

On the second plug in, you should have #2 a black and light blue wire grounded and #16 a grey and yellow wire should be battery voltage in run or start.

Check to see if you have all the power and grounds to the module before you do anything else. If they are all good you may have a bad module. You may have a bad switch but you have to start somewhere... and since the module was gone, it would be logical that they removed it because it was bad. However, that doesn't necessarily mean that if the previous owner didn't have a clue what he/she was looking for.

Thanks so much carriedi. I will check this first. someone told me I have to get the module programmed for my vehicle???

I don't think it needs to be programmed but you may want to use a scanner and look at the module for codes or if it is alive

I found out that Ford make a boo boo with the early module. If/when you disconnected the battery, it ruined the 4x4 module. Ford has a replacement for it now, but wouldn't cover it with warranty. Thing is, they say it needs to be programmed before it will work.