Electrical, brake lights, shift indicator (selected gear indicator lights)

Problem: once engine is started there is a new and clearly audible "clicking sound" from within the dash directly in front of driver (sounds like an old time flasher relay clicking) with each click all brake lights are coming on and off on the vehicle. In addition, not always, but much of the time the light that indicates which gear is selected (on dash, D, P, N.) Are getting bright and dim or going on and off. Typically after I shift gears to back out of driveway, it stopps? The only thing that comes to mind other than a short of somesort is the emergency flasher relay, but I do not know its location, so I don't know. Any thoughts? I usually do my own repair work so I would apreciaete a suggested answer or process.
Thanks
Ron