Parking Light Problem

[ExplorerV6]

When I turn the parking lights on in the Explorer nothing happens. No exterior lights light up, no dash lights come on, the radio does not dim, and if the door is open and the key is out of the ignition than the door does not make the "dinging" sound that it should. All of these conditions are exactly the same when the headlights are turned on except that only the headlights themselves come on. No other exterior lights come on, no dash lights come on, and the open door does not ding. Every once in a while when the switch is turned, everything will work properly, but this only happens about 10% of the time. I have checked the fuses and am not sure where to go from here. Any help would be greatly appreciated.

One other thing that I have noticed is that whenever this problem occurs the 4x4 lights on the dash do not work. The 4wd works as it should but the lights do not come on.

 

[Cobraguy]

Well, my first thought off the top of my head is the dimmer switch. The power for the 4X4 lights and cruise control light in the dash come from the dimmer switch. (unplug the dimmer switch and those indicators don't work) But to be honest, without taking time to go over all the wiring diagrams, I'm not sure how viable a solution that would be for all your symptoms.

 

[ExplorerV6]

Thanks for the idea.
Is there any place that I can get the wiring diagrams to look at?