Assuming you've used the plug in loom you can get from Halfords, etc, the CD player shouldn't be a problem - I 've put a Sony MP3 head unit in mine, with no such issues. However, my fog light has a nasty habit of blowing the same fuse you're losing - rear lights and internal dashboard illumination. Check that your fog light isn't on next time you change the fuse and check again. Don't know how long you've had the truck, but if you are a new Daihatsu owner, I'm sure the others on here will back me up, you'll need to get handy with autoelectrics, they are notoriously dodgy on that score. Why the Japs made a truck so incredibly capable in the muddy stuff, then made the wiring, especially at the back end, so open and exposed to the elements is a mystery to me, but it's one of the many joys/nightmares of owning one of these mighty beasts.