Installing one led in signals for instance will give you a hyper flash. Installing more will make the flash worse or completly stop flash at all. I know I tried it one at a time. I had to get a led flasher to compinsate it(resistors do the same). It sounds simular to your fogs. It's kind of like a let you know feature for people that never check that stuff. Your blowing fuses cause it is about 90% power return with the leds. So it blows a fuse. Like if you had an accident and break both lights, it will pop the fuse to prevent shortening elsewhere and you can drive it to get it fixed.