2000 Other Mitsubishi Models NO LOW BEAM HEADLIGHTS

VIN #JW6AAF1H5YL008565

This truck has no low beam headlights unless you have it on high beams then all four lights work (4-light system). I've checked all the fuses and relays, OK. I pulled the headlight switch, ohmed it out and checked all voltages, OK. I think there is a break somewhere in the wiring harness but not sure; would like to see if you could supply me with the wiring diagram for the headlight system.