I'm installing a radio in my 86 720, but I think this *thing* is blown. The red power wire has this black, cigar shaped *thing* a little larger than the size of a AA battery. The red wire connects to the *thing* from one side, then comes out the other side before going on to the radio's red power wire. It isn't the 1.5A fuse. It is on the red power wire between the 1.5A fuse and the radio. --- Anyways, I need to identify it because I think it is broken. I've tested all the other fuses. The 15A fuse isn't reading anything from the fuse block, even with a new 15A fuse. The yellow memory fuse is no problem. The red power fuse reads 12v. But, when I test the black *thing*, one side reads 12v; the other side has an inconsistent reading. That is the side that broke, but I soldered it back on. Can anyone identify this *thing*, or help me figure out what I've done wrong?