CalAmp LMU-3640 Installation Guide

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This article will assist you in successful installation and validation of telematics devices using the CalAmp LMU-3640 according to the configurations designed by Utilimarc Telematics. The part number for this device is "LMU3640LAB" or "LMU3640LVB" depending on the mobile network of the device.

Kits using this device contain a subset of the parts pictured below:



Step 1:  Record Vehicle Information

If the vehicle data is not already associated with the device, the first step of the installation is to record the following information prior to plugging the telematics device into the vehicle:

  • Unit number

  • VIN Number

  • IMEI/MEID/ESN Number located on the back of the device

  • Current vehicle odometer reading

  • Current vehicle engine hours, if available

The vehicle data should be recorded on our online fillable form.


Please fill out required fields (Company Name, Unit ID, ESN located on the back of the CalAmp device, VIN, Odometer Reading) and submit the form. You will receive an emailed summary of the action taken from once it is complete.


More information for the fillable form can be found here.

Step 2: Plan the Installation

Verify Power, Ground and Ignition: Be sure to check each source (power, ground and ignition) to ensure that the proper signaling exists. This is typically accomplished with a multi-meter.

  • The power signal should be representative of the vehicle battery voltage.
  • The ignition signal should provide voltage only when the ignition is engaged.
  • The ground signal should be connected to chassis ground.

Before drilling any holes or running any wires, decide where each hardware component will be located (LMU, peripherals, etc.). Be sure that the cables to the LMU are not bent or constricted in any way. Also make sure that the LMU is kept free from direct exposure to the elements (sun, heat, rain, moisture etc...) as improper installation of the LMU may void the warranty.

The best way to ensure a trouble-free installation is to consider your options and make some decisions before you start.

Take a look at the vehicle and determine how to best install the LMU for the following purposes:

  •  Accurate data gathering and simulation of how customers actually use the solution
  •  Ongoing monitoring and maintenance of LMU equipment
  •  Prevention of accidental or intentional alteration of the equipment or cable connections

Device Placement: Find the OBDII connector of your vehicle and plug your device into the port. In general, the OBDII connector is located to the left of the steering wheel underneath the instrument panel. In some cases, the OBDII connector is located behind a protective panel that may have to be opened. In this case, the CC-102 splitter cable can be used to extend the OBDII port so the telematics device can be put in a more desirable location. The cable comes with a selection of re-mounting brackets to provide a port for garage diagnostics devices to plug in.

It is critical to note that there SHOULD NOT be any other device on the OBDII connector along with the LMU-3640 during normal operation. Having another device on the OBDII connector along with the LMU-3640 will cause the telematics device to malfunction.

Status LEDs: Lights on the front of the LMU unit can provide valuable information about the operation of the LMU. When feasible, attempt to install the LMU in such a way that these lights can be seen with reasonable ease.

You may find it useful to be able to view the LEDs periodically to make sure that the LMU is operating properly. If at any time you should encounter a problem with the LMU, you may need to read the LEDs in order to troubleshoot the problem. If you cannot fix the LMU yourself, you will need to provide the LED information to Utilimarc customer support.


Vehicle Hardware Input Signals: The LMU-3640 provides up to 4 digital inputs. These inputs are protected from typical vehicle transients and can be directly connected to most vehicle level logical inputs from 4 volts up to the vehicle power input level (typically 12 VDC). Their input impedance is approximately 10kΩ. One of these inputs is dedicated to sensing the vehicle’s ignition status to provide for flexible power management. Inputs should provide a positive voltage signal when the hardware is engaged and otherwise remain neutral. If the hardware to be tracked (PTO engaged, Boom out-of-stow, etc) provides a ground signal when engaged, use a relay to reverse polarity of the input before it reaches the device. 

Step 3: Device Installation

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, 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.

Voltage must be equal on the red hardwired connection and the vehicle bus connection (OBDII, J1939, etc). Failure to connect these lines in the manner described may result in discharge of the vehicle battery or damage to the device.

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.


Consult the LMU-4230 guide for more information on input wiring and logic

Step 4: Data Validation

(See Data Validation article)

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