2000 Chevy S-10 Headlights

When The ignition is on, no matter what position the light switch is set to, all of the lights outside the truck are on. The only time the switch works right is when the ignition is off. The other issue that is certain to be related is high/low beam operation. With high beams off, all four of the headlight bulbs are lit, the outside bulb on the driverside is bright, and the bulb closest to the grill is dim. The bulbs on the passenger side are both lit, but dim. When high beams are selected, the bulbs on the driver side switch, outside bulb becoming dim and grill side bulb becoming bright with once again no change of any sort on the passenger side. Could this be an issue with the Daytime Running Lamps/Automatic Exterior Lamp Control feature, and is there any way I could find out without having a comp. Diagnostic done?