User's Manual

14221-1200-4010, Rev. B
53
3. Route the red wire and the CAN cable through existing channels in the vehicle body to an area near
the vehicle’s firewall. Leave service loops at the rear of the radio. CAN cable installation is
completed later using the control head installation procedure (Section 10.5).
4. Continue installation of two (2) DC Power Cables by routing their 20-foot red wires to the location of
the vehicle’s battery (or its main DC bus bar or stud). Route the wires through channels in the vehicle
to the location of the battery. Protect the wires from possible chafing where necessary. Tie and stow it
as necessary.
Plan the routing of the two red wires carefully, using an existing access hole in the vehicle’s
firewall if possible. Alternately, drill a new hole approximately 3/8-inch in diameter and
install a small rubber grommet to protect the wires from chafing on the hole’s sharp metal
edge. To prevent fumes from entering the passenger compartment, this
hole/grommet/wire combination must also be sealed with a silicon-based sealer before
completing the installation.
Do not install any wiring or fuse holder over or in the near vicinity of the vehicle’s engine.
Excessive engine heat can cause permanent damage to these components and can lead to
intermittent electrical connection to the battery.
The white wire of both units’ DC Power Cables requires no electrical connection. Rather
than be cut from the two cables, it is recommended that these wires be routed up to the
vehicle’s fuse box, coiled, labeled, and stowed for possible future use. The white wire of the
control head’s DC Power Cable is the radio installation’s ignition sense input for on/off
power control of both the control head and radio. Radio on/off power control is
accomplished by the control head. The control head “wakes-up” the MRU radio via data
activity on the CAN link.
5. Get the two (2) inline fuse holders included with the DC Power Cables.
6. Observe and abide by the following WARNING!
Before making connections to the battery’s positive post, carefully disconnect the
battery’s negative (ground) cable(s). This will prevent tools or other metallic objects
which come in contact with the battery’s positive terminal from shorting to vehicle
ground, causing sparks or even a fire or an explosion!
When disconnecting the negative cable(s), cover/insulate the positive post(s) so a tool
cannot short between the posts. Some vehicles, such as those with diesel engines have
more than one battery; in this case, disconnect the negative cables at all batteries.
Radio and control head fuses should not be installed until all wiring is complete. This
will prevent the radio from powering up prematurely and/or causing an in-rush of
current that could lead to shorting of the battery, sparks, or even fire.
7. Cut the red wires to the required lengths for connection to the battery’s positive (+) battery terminal
(or the main DC bus bar or stud).
NOTE