Witch wires should have power/ Map switch

The brown wire will have power all the time if there is a good bulb in the map light socket.

If the dome light is on (either turning the headlight knob, or with a door open) the yellow wire will be connected to ground, if the dome light is off, then the yellow wire should show some positive voltage because it's feeding through the dome light bulb.

To check the dash wiring without the switch plugged in:

Connect the brown wire to ground, the map light should light up.

Connect the yellow wire to ground, and the dome light should light up.


To check a switch out of the car:

With the switch in the normal position (the map light goes on/off with the dome light) the two prongs on the switch should have continuity.

With the switch in the map light always on position, the prong for the brown wire will have continuity to the metal body of the switch, and the prong for the yellow wire doesn't have continuity to anything.