Headlight Switch Trouble

[n33k0]

I have been scratching my head trying to figure this one out for a while, even though I'm not the brightest crayon in the box when it comes to electrical stuff. The headlight switch in my truck doesn't work correctly, the only lights I can control with the knob are the headlights. Marker lights, dome light, even brake lights don't work when the switch is plugged in!

Somehow I figured that I could hard wire the connection in the plug to test the wiring. I removed the switch and found the hot "POWER" wire in the plug, then ran a short lead to each terminal to test the lights.

Run a wire from "HEADLIGHT" to "POWER" and the headlights turn on, "MARKER LIGHTS" to "POWER" and the marker lights turn on... When I have these three terminals wired to the "POWER", the lights are on and everything is great... but when I put the switch back on, only the headlights work.

If I have the switch on, I found that I could run a lead as shown in the pic below, then the switch would work perfectly... I can dim the cluster lights, I can turn on the dome light, the brake lights work too, but only if I run a wire as shown by the blue line.


What is happening here? there is obviously power reaching the switch... but I have tried three different switches and none of them work without the modification I have mentioned above.

Any help would be appreciated.