Flash “d” indicator light

a flashing d light is generally a sign of a tranny problem and there will be a code stored but it sounds like the issue is with your cruise not setting and a code should be stored for it also

I have the same issue of the D indicator light flickering, and it seems to me to be a weak (corroded?) electrical connection on the gear shift knob. If I wiggle the gear shift knob, it makes a solid electrical connection and then it is OK. Sometimes while driving with Cruise on, it will suddenly shut off the Cruise, synchromized exactly with the flicker of the D light. Again, I wiggle the gear shift every so slightly so the D light glows solid, and then the Cruise will work again. I would like to know where the electrical contacts are so I can inspect them and clean them.