How your Headlight Motors Work., A description with pictures. Options

[ClayPerrine]

NOTE: DUE TO MY NOT LOOKING AT THE WIRING DIAGRAM BEFORE POSTING THIS, I HAVE EDITED IT TO REFLECT REALITY!! (IMG:style_emoticons/default/headbang.gif)

I noticed that there is a lot of questions out there relating to how the headlight motors work. So I put this together to see if I can clear it up.

The headlight motor circuit functions like a 3 way light switch in your house. You all have seen them. The one you can turn on at the bottom of the stairs and turn off at the top. Well, when you turn on the headlights in a 914, you turn on the headlight motor. It's rotation turns off the headlight motor when the lights are up, using a set of wiper contacts in the motor.

In the first diagram below, I outline the headlight circuit with the lights in the down position.

[ClayPerrine]

Now we turn the headlights off. The headlight switch connects power to the off contact, and that supplies power to the "closed when up" wiper contact, which then feeds power through the common contact to the relay coil. The relay energizes, connecting pin 87 to pin 30. That supplies power to the headlight motor to make it start moving down.

When the headlight reaches the down position, the wiper contacts connect the common pin to the "closed when down" connection, breaking the circuit to the relay coil, and that turns off the power to the motor.