Auto headlight needs to be manually operated?

[skaif]

Hi guys, I have a 2007 Yukon XL on the GMT900 platform and the auto headlights are acting strangely. 

 

If I start the car from cold the auto headlight switch needs to be manually flicked to 0 and back again to activate the auto headlights, once I have done this the auto headlight function works for the remainder of the car being on. Once I turn the car off for more than a few minutes though I need to repeat this process to get them to work. 

 

The headlights work normally when I manually switch them to sidelights and low beam / hi beam but the DRL's (the small orange side light blinkers) don't turn on during the day at all no matter what I do. 

 

Any ideas? 

[skaif]

Anyone had anything similar? 

 

How are the DRL supposed to work? First time owner of this type of car so its all new to me!