Being a flatlander in FL, I have not used my DAC on my truck except a few times just accidentally hitting the button. Well I am visiting family in central TX and with the illy roads I decided to see if it did anything. Mind you I was in 2WD, not 4lo/AWD so the light flashed on the dashboard and beeping started, once I realized it wasn't doing anything I clicked the button again and the flashing light went away. Except the beeping didn't stop. Now I cannot stop the beeping and I have a 1200 mile drive home starting tomorrow and I am going to lose my mind if I can't get it quiet. I will literally pull the appropriate fuse if it helps but I can't figure out which one it is.
Any suggestions? Ideas? Thoughts?

Forgot to mention the VSC/TRAC lights are on, have been for years, never bothered me and never made a difference in driving the truck.

Were you on a road? DAC is for off-road use & only works in 4LO so that explains why nothing happened. Can’t help you with the beeping, but I’d start with cycling through all the 4WD modes.

Maybe if you can track down where the "beeper" is you can try and disconnect it?

That was my first instinct, once I realized the beeping wasn't going to stop I switched to 4Hi and pressed the DAC button but it didn't do anything. I have also disconnected the battery and left it that way for about 20 minutes to allow the ECU to reset. No improvement. I'll try it in 4LO next, luckily the roads in this neighborhood are caliche.

@bluesky 07 is spot on - best bet is to just be patient and try cycling through all of the 4wd modes. Good luck. Let us know how it goes.

I've owned my 4th gen since 2008 and I've actually used the DAC exactly once, just to see how it worked when it was new. I don't like the noise it makes and I prefer to control the brakes when I'm off-road. Just my $.02

As for your issue, it sounds as if the transfer case is between drive modes. Generally, just bumping the DAC button doesn't cause it to beep (my dog smashes that button every time he gets in or out, lol). I would try to cycle the 4wd modes and see what that does. Ultimately, the fix may be getting the cause of the VSC/Trac lights repaired, whatever that is.

Managed to find some undeveloped roads nearby and cycled 4wd on and off a few times including locking the diff and engaging DAC and actually letting it work a couple times and the beeping finally quit. What a pain, crossing 300k miles has been painless up till now.