W123 light switch pin-out

ahoy:

i have a problem with my mother's W123 light system. the headlights (low and high beam) do not go on with the light switch in the 'on' position (two clockwise clicks from 'off'). parking lights, blinkers, &c. all work. fuses are good. high beams illuminate when i pull on the directional lever (flash high beam function) so i know the lights are ok. i suspect the switch.

i gained access to the switch, but do not know the pin-out. what i'd like to do is short the wires that would connect with the switch in the 'on' position - to verify the switch is bad. can anyone tell me which wires to short in order to simulate a good switch in the 'on' position?

thanks very much.