Electrical 579 Family
Peterbilt Motors Company 7-1
SECTION 7 ELECTRICAL 579 FAMILY
INTRODUCTION
This section is written to provide information to the body builder when installing equipment into vehicles built with
Multiplexed instrumentation. The new technology presented by NAMUX 4 level instrumentation integrates J-1939 CAN
data communications to various equipment on the vehicle. This book is intended to address how to work in aftermarket
equipment while still maintaining full functionality of the OEM vehicle.
The most important advancement of NAMUX 4 instrumentation is the implementation of the Cab ECU controlling air
operated aftermarket devices. While it is still possible to wire completely outside of the Cab ECU system, utilizing the
CECU functions will make a cleaner installation and will maintain OEM functionality. NAMUX 4 expands controls to air
operated devices by receiving input from dash switches, remote (aftermarket) switches, sensors mounted to the
aftermarket equipment and other vehicle parameters (engine speed, transmission status etc.) With the proper
programming, the CECU will then process the inputs and will create a J-1939 Data instruction which is communicated to
another controller outside the cab called the Chassis Node. This chassis node receives the instruction and connects 12V
power to an air solenoid. 12V power will open the solenoid and supply air pressure to that air circuit.
FIGURE 7-1. NAMUX 4 System Diagram
In addition to NAMUX 4 technology, the vehicle electrical harness has been redesigned to minimize weight and reduce
various connectors (which have been proven to increase the opportunity for electrical malfunctions which also increase
the amount of time to troubleshoot). What this means for the aftermarket installer is that there is a limitation to modifying
a vehicle with aftermarket equipment if the vehicle was not originally specified for those options from the factory. To the
aftermarket installer, more time will be spent installing pins and routing wires instead of simply installing jumper harnesses
if the vehicle was not specified with ‘customer installed’ equipment from the factory. For example, vehicles ordered with a
‘customer installed’ PTO will have connectors on the vehicle for aftermarket connectors. A vehicle specified with standard
radio will not have a pigtail for premium sound speakers.
