Thanks to everyone that supplied me with info about my auto headlights. I purchased both the switch and the sensor. Turns out the sensor was the problem (thanks to Bull Geek). Plus my climate control AC works much better. Seems the sensor has a dual purpose....light sensor for headlights on/off and AC sensor for regulating the temp on/off controls. I replaced it today but haven't had a chance to see if the lights work although they stay off with switch in auto position so thats a good sign. When it gets dark out I'll check the full operation of the auto lights but I'm certain they will work fine. Thanks again for all your help.....saved me about $200.