Strange issue popped up. When the truck ignition is put into ACC, I get the normal double chime (seatbelt), but the minute I go to shift, I get a constant chime (same tone) when I hit the shifter button. It only happens when in Park and in Neutral, no other time. If I hold the button, the chime continues as a consistent noise.

I've cycled the T-Case shifter and the Trans shifter multiple times, no difference. This all popped up after I tapped the 12V wire for the CD Changer to install an accessory. I reversed the tap, but this issue persists. Any ideas?

 

Figured it out. Fuse 12 under the front fascia had blown. Not clear why this caused beeping with the shifter in N and P, but its fixed now.

 

That must be the highly specialized "Fuse 12 is Blown" alarm function. Those clever engineers!