Headlight switch problem

I have had alot of trouble lately with my headlight switch.  I came home from college and charged my cell phone in the cigarette lighter.  Tryed the headlight switch the next day and it would kill the van.  So I replaced the headlight switch...not any better.  Looked behind the battery and found that a piece of the wiring harnes was damaged, replaced that still no better.   I tried to by pass the wire and found its not in the red wire form the switch to the power source behind the battery.  I am almost 100% shure that it is killing the fuel pump when the switch comes on.  It also resets the radio.  The 20amp fuses which i think the wire to the headlight switch is were blackened one side so i replaced those and it still continued with the same problem. Does anyone have any idea what the deal is?? Thank you for you time. 

Are there any modifications to the lights... trailer harness , fog lamps ??

I haven't modified the lights in any way.  I use the fog lights that came standard on the van.

quote:

ORIGINAL: flynnstone_45

I have had alot of trouble lately with my headlight switch.  I came home from college and charged my cell phone in the cigarette lighter.  Tryed the headlight switch the next day and it would kill the van.  So I replaced the headlight switch...not any better.  Looked behind the battery and found that a piece of the wiring harnes was damaged, replaced that still no better.   I tried to by pass the wire and found its not in the red wire form the switch to the power source behind the battery.  I am almost 100% shure that it is killing the fuel pump when the switch comes on.  It also resets the radio.  The 20amp fuses which i think the wire to the headlight switch is were blackened one side so i replaced those and it still continued with the same problem. Does anyone have any idea what the deal is?? Thank you for you time. 

What happens when the light switch is turned on and the van is not running ?
Do the dash lights go ut as well ?

You say it resets the radio memory will it shut off the radio ?

So far it's sounding like a loss of battery power. If you haven't done so yet... clean the battery cable and battery terminal connections throughly to start.
Another thing is how good is the battery ? 

when the van is on and then i turn the switch on it dies.  the dash lights as well go out, the radio shuts off and resets the time.  I'll take a wire brush to those cables today, but the look clean-no corrosion.  the Batter was replaced in October of 2005 so its not that old.  I just can understand why fliping a switch kills the whole vehicle. thanks for you time guys it very much appreciated

Try turning on the wipers , radio , heater and anything else at once other than the lights to see it does the same thing.