Welcome to JustAnswer, my name is XXXXX XXXXX I'm here to help get your problem resolved. This most likely means the 4wd control module has failed, it has a built in relay which is what you are likely hear click. These modules have alot of problems, here are replacement instructions. Let me know if you have any questions, thanks.
Where can I pick up a new module and what does one cost? I looked it up on internet and cannot find the part with that part number.