It is always something little. The big things are easy.

 

My tail lights have been working fine since day one. I drove home from work the other night in the BRAT and the tail lights were fine. The next evening I drive to the store and the tail lights are dark (brake lights are fine). So I check the fuse and it is blown. I install a new one and everything works fine for about 2 min. then it blows. Same result on the second fuse (done just to prove to myself it really happened.

 

A simple short to ground would blow the fuse near instantly. Had I used higher amperage bulbs that pushed it over the fuse rating by a smaller margin I could see it taking a few min to blow. But the bulbs are the same ones I had last week and they all glow per usual until the fuse goes. Short of the evil component fairy soldering a low value resistor to create a overcurrent of just a few amps this makes no sense.

um I heard this explanation for something similiar but dont know if its right or not, but it goes like this: A weak ground causes a voltage drop, causing the lights to draw more current instead, causing the gradual fuse blowing. Or something like that. Anyway, it cant be too hard to take off the ground wires and clean em up.