When I got home from a week and a half trip the other day my car battery was dead and in the process of getting a jump, it shorted out my radar detector cord (the radar detector itself was not attached). This also happened the last time my battery almost died. I ordered a new cord and when I plugged it in, it light up for half a second and then immediately shorted out as well. My friend checked the fuse and it was fine. He then plugged in the car charger for his phone and it worked just fine--it did not short out. He recommended buying a capacitor. Is that the best solution?

 

Sounds like the plug port is damaged.......try it in a different port, if it works plugged in elsewhere in the car you have the answer.