Did a search but didnt come up with much... was workin on my truck at work and when i was leaving i noticed the door ajar light was still on as well as the interior lights. Check all doors...closed....
Ideas...??? Where is the switch on the drivers side front door?

 

The switch in in the latch mechanism. Spray it down with wd-40 and it should straighten up. They get dirty and stick over time.

 

And if that doesnt work then you will need to replace the latch assembly. In it is also the door ajar switch and the dome light switch. There are several threads on this where others have had this issue and had to replace it including myself.