Audiovox VOD850 - Manual (Page 6)

6
Mounting the Trim Ring
Roof
Roof Support
Hardliner
Mounting Bracket
Self-drilling Screws
Trim Ring
Video Unit
M4 Flange Nut
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 the 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 the lights
out, both wires at the dome light will rest at + 12vdc. When the light is activated, one of
these wires will switch to ground. This is the switching wire.
For positive systems, connect the violet / 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.
4) Once the mounting location of the monitor has been determined, there may be
additional preparation work necessary, depending on the vehicle structure and
installation method. Some of the steps that may be required are:
A)
Removal of the vehicle's dome light
B) If the trim ring will be used, it may have to be trimmed to fit the contour of the
vehicle's headliner.