Connecting the Dome Lights

The dome lights in the video monitor require three connections to the vehicle's wiring. There are two common types of dome light circuits used, positive or negative switched. Positive systems supply voltage to the interior lights to turn them on. Negative switched systems apply ground to illuminate the bulbs.

To determine which system you have, you must locate the wires at the dome light. On a positive switched system, with all the doors closed and lights out, both wires at the dome light will rest at ground. When the light is activated, one of these wires will switch to +12 VDC. This is the vehicle's switching wire. On a negative switched system, with all the doors closed and lights out, both wires at the dome light will rest at +12 VDC. When the light is activated, one of these wires will switch to ground. This is the switching wire.

For positive systems, connect the purple/brown (Lamp auto) wire to the vehicle's switched wire. Then connect the red/black (Lamp on) wire to a fused constant 12 volt source and the black/red (Lamp common) wire to a good ground. Positive systems are commonly found on Ford vehicles.

For negative systems, connect the purple/brown (Lamp auto) wire to the vehicle's switched wire. Then connect the red/black (Lamp on) wire to a good ground and the black/red (Lamp common) wire to fused constant 12 volt source. Negative systems are commonly found on General Motors and import vehicles.

Note: Some vehicles which incorporate transistorized control of the dome light circuit, such as the 1999 Dodge Caravan, may require that the purple/brown (Lamp auto) wire be connected to the door pin switch wire, as the additional current draw of the Monitor's lights may not be supported by the output of the vehicle’s body control computer..