I have posted this question in the DRZ forum also, but no answers. I installed these a few weeks ago, when it was still warm. They worked as advertised. Now that the temperature has dropped, I have tried using them 4 days below 40 degrees with no luck. The light comes on for 2-3 seconds, then turns off. Once the outside temps creep up however, they work fine. The battery is good and I installed per their instructions directly to the battery. It is not a low battery turn off either, as the light flashes if that's the case. It is the model OF 699 if that makes any difference. The voltage seems to be within range as well with bike running. I'm desperate for answers as I want to ride as much as possible this coming winter without getting frostbite. Thanks!