The instrument cluster IPC turned out to be my problem. It came out very easily and I sent it to a Speedometer Shop in Sallisaw, OK for repair, believe it cost a little under 100.00 dollars. A little difficult to diagnose because the excess draw/short was not always consistent. The install of a back up battery pack is a great idea, but I would still get the problem fixed.
My father's 2003 has the same problem. Pull the IPC/DIC and the draw reduces to 3.22 mili amps. I have been trying to fix it for the last two days. I was hoping that the instrument cluster itself wasn't the problem. He bought new and it only has 50,000 miles on it. If Louis /GM Customer Service is still available the last 8 of the VIN is 31185462.
Thanks for any help or suggestions