Not sure what manual you are looking at, I tried your test on a known good and known bad acting headlight motor, they both just ran on and on with 12 volts applied.
The control unit indeed clicks. Those are internal relays that switch power on and off to the motors.
With the headlights down, the controller senses from the motor cams, via one of two sense lines per motor, that the motor is in the down state. That is the purpose of those non-copper areas of the cam, at the headlight up and headlight down physical positions. If the headlight switch is off, it keeps things in this state, headlight down, motor power off.
When headlight switch is turned on, the controller senses an out of balance condition, that is, the lights are on and the headlight is down. The controller then energises the relay, supplying volts to the motor, click.
The controller continues to monitor the cam position lines. When the motor is raised fully, the sense line indicates this, and the controller de-energises the relay, turning off volts to the motor, click. Headlight on, headlight raised, controller is happy.
Same thing happens now when the switch is off and the headlight is in the raised position. Power on, headlight eventually sensed 'down', power off, click click.
Those 17 pins are power lines out to the motors, grounds, inputs from the motor cams, inputs from the headlight switch, pull-to-pass, console switch...
Relays in the conroller are real manual switches, and can go bad, it's just that I've dealt with and heard about many headlight issues, and only once was the controller at fault...