02 trailblazer 4x4 flashing lights issue! please help

[superwade57]

hi guys i spend my time in the 73-87 board, however i own an 01 tahoe and 02 trailblazer....which is my problem today.

my wife recently reported to me, while driving in 2hi the light above 4hi is lit up and the light above 4lo is flashing. that didnt alarm me much since we have two toddlers i assumed one of them bumed the switch and it was trying to engage after the fact, i had her pull over put in N switch to 4lo then to 4hi then to a4 then 2hi, just to cycle the transfer case. however when pulling into or out of a driveway or parking space it will intermittently bind up like its in 4lo then after a few moments clunk hard upon what seems to me to be 4lo disengagement. that has happened to my wife a couple times, so upon HER description of the issue i put it on the lift and pulled all the wheels all the calipers and all the pads which are and were almost new. after throroughly checking drivetrain i put it back together and decided to drive it for a couple days as the problem is very intermitent. my first and only experience with the problem was backing out of a parking space, the wheels bound tight, i gently powered through it, wheels chirped and acted like 4lo, switch still in 2hi, dry conditions, drove aprox half mile to next store, truck felt a little weird while pulling into store lot when i noticed the lights were lit as when my wife told me they were when she was driving down the highway days before... switch in 2hi, light above 4hi lit steadily and light above 4lo was flashing. then huge disengagment clunk, weve only had the truck a short while. after i pulled it off the lift the day before, i engaged disengaged and tinkered with 4x4 for several minutes to look for issues since my thought was if i cant find anything with the wheels maybe the lights she described days before were a clue. point being it was very smooth and quiet when in the shop, and all did work properly.

sorry for the novel but im trying to be a specific as possible, im guessing this may be a bad switch? had seen similar problems online while searching and they say 4x4 module? but havnt seen any of the exact problem upon searching. side note, truck 100,000 miles and an I6 02 LT

thanks for your help!