Just got a couple Federal Signal SIGM2F Deck halogen lights for the car, but when I plug them into the cig. outlet to test them, only one steady-burn light comes on. This happens with both lights, and I figured I'm not doing something right, so I come to the experts . I simply attached a cig. plug to the end of the 2 wires (like it shows in FedSig's instructions), but I keep having this problem. Any ideas?