If you have an ohmmeter then here's the way. Let's name the three terminals on the diconnected headlight A,B,and C. You are going to measure small amounts of resistance so use a good ohmmeter. Measure each terminal to the others...AB=?ohms, AC=?ohms, BC=?ohms. The largest ohm reading, say AB=6ohms identifies the hi/low terminals. The next highest reading, say AC=4ohms is your low beam. The lowest ohm reading, say BC=2ohms is your high beam. The C terminal is ground. Good luck
