Eonon "warning"
DVD head units have one extra wire in their wiring harnesses, compared
to a standard CD head unit. On mine, it's a peach-colored wire, and is
the activation wire for the DVD feature. During the installation, the
instructions call for this wire to be tapped into the emergency brake
indicator light wire. The reason is this:
The e-brake indicator
light is what is called a "ground complete" circuit. That means that
the bulb always has power applied, but when you pull the brake, that
puts a ground to the wire and completes the circuit, allowing it to
illuminate. The head unit sees this ground, and activates the DVD
player.
In my Jensen unit, I simply ran this wire to a ground (I
used a screw near the fuse box), and I put a switch on the wire, so I
could break the ground contact at will. Jensen calls for a procedure to
activate DVD playback. In their instructions, they tell you to select
DVD from the option menu, and when the "lawyer screen" comes up (the
one warning you to park before you watch a movie), you release the
e-brake for 3-5 seconds, and then reapply it. To simulate that with the
switch I used, I leave the switch closed (activated), and select DVD.
Then I flip the switch "off" for 3-5 seconds, and flip it back "on".
This tricks the head unit into thinking I put the e-brake off for a few
seconds and then put it back on, and the movie will start. Then I can
drive away.
Basically, ground the wire that is used for DVD
activation, and put a switch inline on it. Then you can break and
reapply the ground in whatever manner is required by the manufacturer
of your head unit. If there is no off/on sequence with yours, as there
is with mine, simply ground the wire to a screw inside the dashboard
and you're done.
