I have a 2005 Uplander AWD with DLR and auto-on headlights. For the past 2 weeks (as cold weather settled in) the auto-on has become eratic. You generally know it is working, even in daylight, when the instrument panel dial arms become backlit. Then, in darkness, the system goes on and off as needed. Lately, I start up the van and the backlighting is off, and there is no response to darkness. Often, the system goes on again after the interior warms, up 30 to 60 minutes later. At all times, the headlights and parking lights can be turned on manually, but if the auto-on headlights system is inoperable then the backlit dial arms are not illuminated. Any thoughts?