1997 Ford Contour Electrical Problem

My friend has a 97 Ford Contour. The Dash Lights and the Tail Lights do not work when the headlights are turned on.
All of the dash fuses were checked and are okay. Is there an underhood fuse or relay that could be causing this?

bad headlight switch, or loose conection somewhere between the switch and the lights or possible a loose ground. try smacking stuff with the switch on and see if they start working, hit the dash, steering column, switch tap on the instrument cluster. ford has the wiggle test i have the slap test, probably the most effective way of finding electrical faults. just don't hit anything hard enough to break it!!