MM-010019-001, Rev. B
46
9.4.2.2
Control Head and Radio Turn On with a Manual Switch
With this wiring configuration, the control head and radio are manually turned on and off via an on/off
switch mounted separately from the control head and radio, not through the vehicle’s ignition switch/key.
This configuration is used when, for example, the radio must remain on even when the ignition key must
be removed from the vehicle and a separate on/off switch is acceptable. In this configuration, the white
wire connects to a switched power source such as a toggle switch mounted on the vehicle’s dash. When
using this configuration, the CH-721 control head’s on/off/volume control must be left in the on position
for automatic power-up/down to function properly.
1.
Route the white wire of the control head’s DC Power Cable from the back of the unit to an area near
the on/off switch’s location. At the back of the control head, be sure to maintain a cable service loop
of at least six (6) inches.
2.
Cut a short section (6 to 8 inches) off the end of the white wire and strip the ends.
3.
For a new on/off switch (not supplied):
(a)
Tap a wire off non-switched battery power from the vehicle’s fuse box with an 18-AWG wire.
(Use wire remaining from the power cable, if available.) Keep wiring as short as possible and use
approved wiring methods. Use techniques presented in Section 9.4.2.1 as a reference.
(b)
Strip and crimp this wire tap to one side of the ATM fuse holder. This holder is included with
Vehicle Fuse and T-Tap Kit, item 7 in Table 4-3. It has built-in crimpable joints.
(c)
Crimp the short wire to the other side of the ATM fuse holder and connect the other end of this
wire to the common terminal of the manual switch.
(d)
Connect the white wire of the power cable to the load (switched) side of the manual switch.
For an existing switch:
(a)
Crimp the short wire to one side of the ATM fuse holder and connect the other end to the load
(switched) side of the manual switch.
(b)
Crimp the white wire of the power cable to the other side of the ATM fuse holder.
4.
Install the 2-amp ATM fuse into the fuse holder. It is recommended that a piece of electrical tape be
wrapped around the fuse connection to keep the fuse from being jostled out of the holder.
5.
Tie and stow these wires as necessary so they remain out of the way of casual contact and wire chafe
is avoided.
6.
Label this power switch accordingly. For example: “
RADIO ON/OFF
.”
9.4.2.3
Control Head and Radio Are “Hot Wired”
In the “hot-wired” configuration, the control head and radio are turned on and off only by the control
head’s on/off/volume control located on the front panel of the control head. In this configuration, the
control head’s white wire must be connected to
unswitched and fused 12-volt
vehicle power. Follow the
procedure presented in Section 9.4.2.1, except connect the white wire to
unswitched
battery power
instead of switched (“Accessory”) power.
