I have a 1999 Yukon Denali 4x4 V8. I just purchased it used obviously and after buying it I took it to a mechanic to make sure it was sound. well it has been 3 days and now all of a sudden the battery dies because when I take my key outta the ignition the radio and the windows still have power to them. I am clueless as to what may be the cause of this. Can someone please give me some information on this or steer me into the right direction?

It seems the RAP(retained power accessory) is staying on when it should be shutting off when you open the door. I wonder if the RAP has its own fuse you could pull temporarily to see if it stops the battery drain.

So, couldn't you just turn the radio off? The windows shouldn't cause any draining. If it continues, I'd check the alternater diode for your draining problem. $0.02.

99 is old body style, no RAP. probably the Ign switch. there is a plug under the dash has all the ign stuff on it by the steering maybe you can unplug it and see if the stuff goes off

Thanks for the responses....seems like the previous owner had some sort of device wired into the fuse box. the device had a fuse in it which is spliced into the big Silver 30A fuse for the power windows. a temp fix I found is I just removed the fuse and the radio turns off and the windows wont work when the fuse is out but my battery isn't dead. I called autozone to see if they had the silver 30A fuses in which they do not. anyone have a idea where I can get them?

is this what you are talking about? its called a circuit breaker or thermal circuit breaker and the parts stores should have them