highmilesrunner

i have read the 2.5 million threads on flashing 4wd indicators when trying to engage 4wd and i don't see anything that pinpoints my problem. my haunting a$$ indicator flashes when i'm not even thinking about 4wd, only when i'm driving fast, and not all the time at that. it does this following a fast drive on an interstate, but not all of the time.

most recently, i drove about 1.5 hours at between 75 and 85 on the interstate and all was well. i didn't drive it anymore that night, so i get in it the next morning and my indicator immediately begins flashing on and off. i'm scratching my head and have no clue but then remember one time previously when i was driving at high speeds, it did this. so i try the push-button 4wd (2000 limited) to see if that will make it go off but it didn't. only having it sit for several hours and then restarting seemed to fix it. it hasn't done it again but i'm a little worried that it could be something more. anyone heard of this or experienced this craziness?