While doing a check of lights, brake lights, hazard lights on my federal TC, I noticed I lost the main beam headlights when activating the floor mounted dimmer switch and the high beams did not turn on. Pushing the dimmer again, the main beams came back on. After this, I now have no headlights at all. The park/side light switch turns on the park light only. Am I correct in believing the sidelight circuit needs to be operational to activate the main beams and I need to find a park/sidelight switch? The wires to park/side light switch are in good shape and no fuses are blown. I have obtained a new Lucas 103sa dimmer and will install when I can find a wiring diagram to determine which wires go to which terminals.