Typically, the LMU should be placed under the passenger seat or dashboard of the vehicle. LMUs with
internal antennas should be placed to maximize their GPS performance. A typical location include
under the dash close to the front wind-shield.
Attach the LMU to the solid body of the vehicle, not to plastic panels. The LMU can be placed out of
sight by removing interior trim and molding to expose available space, then replacing the trim once the
LMU is in place
5.3.2 Connect power, ignition, and ground.
The power input (red wire) must be connected to a constant (un-switched) +12 VDC or +24 VDC
supply; preferably, connected directly to the vehicle battery terminal or as close to it as possible. This
connection point should be fuse protected to not more than 5 Amps.
The ignition input (white wire) must be connected to the vehicle ignition or another appropriate key
operated line, such as ACCESSORY, ensuring that power to the ignition wire is available only when
the vehicle ignition is on.
The ground line (black wire) must be connected to chassis ground.
Failure to connect these lines in the manner described may result in discharge of the vehicle
battery.
For best results, it is strongly recommended that the LMU connection be on its own circuit. Connect
the power input directly to the vehicle battery if possible and protect the circuit with an inline fuse. If
you must connect through the fuse box, use standard commercial wiring practices to create a
permanent installation rather than using press-in fuse clips or other temporary measures.
DO NOT connect the power cable to the LMU at this time.
5.3.3 Place the GPS antenna.
The GPS antenna must have a clear view of the sky. Mount the GPS antenna on the vehicle’s highest
point (for example, the roof of a car). Make sure that there are no obstructions close to the antenna
that might block the view 360° to the horizon. Air horns lights, vents, etc.. should not block the antenna
beyond 5° above the horizon.
Kinks or knots in the antenna cable can prevent the GPS receiver from operating properly. When
laying out the antenna cable, take care that the cable is not subjected to crushing or strain.
The ideal location is typically near the center of the vehicle’s roof. However, it is also desirable to
locate the cellular antenna as far from the GPS antenna as possible.
