My van's front driver's side headlight stays on and of course, drains the battery in no time. Need help to identify the problem. Thanks.

The headlights are controlled by the Body Control Module (BCM) and the Forward Control Module (FCM). You can try resetting the BCM by pulling the IOD fuse out for 2-3 minutes. It's in the fuse box next to the battery. On the front of that fuse box called the Integrated Power Module (IPM), is the FCM. I've read several posts about corrosion on the connection of the FCM to the IPM causing lights problems. You might try inspecting the contacts on that connection. If corroded clean with contact cleaner and a brush.

DISCONNECT THE NEGATIVE BATTERY LEAD BEFORE DISCONNECTING ANY MODULE.