A month ago I bought a 2000 S-10 Blazer (w/Trailblazer package). It doesn't have an "Auto" setting on light switch. I have three problems:

1) The headlights are always on when the vehicle is running and cannot be shut off (not a big prob). But it is strange that when vehicle is off, key removed, the switch will turn on/off the parking lamps and headlights.

2) Recently, while driving at night, the headlights and dashboard lights shut off! The vehicle has light sensors on the dashboard speaker panels but I don't understand why if the vehicle doesn't have an "Auto" light mode. Are the sensors only suppose to brighten dash lights at night?

3) The dome lights don't work because (I think) I can't find the wires that should connect the passenger door switch. I thought the prior owner cut them but I can't find them anywhere. The dome light override switch works so I use that whenever I want to turn on the interior lights. How can I wire this?

I tried changing the light switch but got the same results for all the above. Could it be an ignition switch problem?

ANY HELP IS APPRECIATED, THANKS.