Re: Headlight switch wiring question

Posted by HH56 On 2015/6/24 21:25:12

The door pillar switches and the headlight switch position for courtesy light are in parallel so all will turn on the light. The headlight switch does have to be all the way to the left to be in the on position. Second notch of switch is all off and third notch is dash lights on and then further turning the knob will dim them until they go out.

If a door happens to be open the headlight switch does nothing as the light is already on but if the headlight switch is in the light position the courtesy lights will stay on when the door is closed.

Here is a disassembled switch. The rheostat and courtesy light portion are on opposite sides of the ceramic operated by the same rotation parts but isolated from one another. The courtesy light portion has a large round plate with a notch which fits over the actual wire terminal. The round plate connects to ground via the case and various portions of the mounting arrangement. When you turn on the courtesy light the wiper that rides against the contact plate goes into the notch area to touch the wire terminal and short it to ground.

If you are unable to read a ground with the switch in on position there is an excellent chance the plates have oxidized or corroded -- a very common problem with the switches as you can see from the condition of the plates in this disassembled switch.

EDIT: I just noticed I grabbed the wrong wiper in my second and third photos. They look the same except the courtesy light portion has a small hole and the one with a large hole goes over the insulator piece on the rheostat side.

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