Fuse Problem...IOD??

Hi all-
Yesterday I drove my 98 XJ from the SF bay area up to Washington. About an hour outside of San Francisco I all my gauges stopped working and the radio lost power. I checked the fuse panel and found no problems and then checked the under hood fuse box and found the "IOD" 15amp fuse was blown. I put in a new one to see if I could get lucky but it blew immediately with the key off. I looked in my manuals today for my old cherokee, an 89, but they don't cover the newer electrical system. What is the IOD? What all is on it? Any ideas what might fail that would cause this fuse to blow? The truck has the infinity stereo in it and it has been doing a few weird things recently...it switches from either radio or CD to tape randomly. I figured it was just a weird fluke or something but now I wonder if there are other problems. Any help would be appreciated...especially if someone has a manual that covers the 98 cherokee and can tell me what is on the IOD circuit. Thanks!!
Andrew
98 Sport
3.5" Rubicon Express

I think IOD stands for "Ignition Off Drain". Basically, it supplies power to devices which require power when the ignition is off.

Such devices would include alarms, door locks, clocks, and of course radios -- to retain station presets, etc.

iod is ignition off draw, it powers dome lamps courtesy lamps , under hood lamp also keylessentry if equipped. unplug one circuit one at a time until the fuse doesnt blow, thats where your problem lies

When I worked on it yesterday I thought the first thing I would try was just replacing the fuse again...and surprisingly it seemed to work. I'm not sure what the problem is now but at least I know what the circuit is. Thanks for the help. I am wondering if it is somehow heat related...like if when the truck gets warm something blows...not sure...but fixed for now...thanks...