Interior Light Fuse Blowing 2004 Cayenne S --need help

[Nicky_Noodle]

I have a 2004 Cayenne S. I just got it recently, interior lights have never worked. I checked the fuse and it was blown. It calls for a 20 amp fuse but the blown one in it was a 25 amp. I had the key in the ignition if I remember correctly and put the new 20 amp fuse in and everything came on. Side note, I noticed a weird glitch with the light above the rear passenger side door and the switch on the main map reading light. The interior lights had gone off and I turned the back on and the backlight above to passenger side door was very dim. I slid the switch on the overhead console for the main map light and the rear light came back to full strength. I found that odd. Everything then worked fine. I took the key out. Next time I put the key in, immediately heard the fuse blow. Any ideas on where to start?