General Information

The electric vehicle power distribution system provides battery power to the electrical and electronic systems.

The following components make up the electrical vehicle power distribution system:

• Battery Cable Access (BCA)

• Electric Vehicle Distribution Module (EVDM)

SAM

CTP

VRDU

VPDM

ECHO Logger

Connect 5

HMC

ECPC

Front Wall Interior Ground Stud

Pass-Through Bulkhead Connector

Fig. 1, Cab Power Distribution and Component Location Overview

Vehicle power is supplied by the batteries to the battery cable access (BCA) box. The BCA front wall pass-through is the primary interface through which battery power gets transferred from outside the cab to the inside.

On vehicles equipped with an optional high current receptacle and/or optional inverter, the BCA has circuit protection and power cables supplying those devices. Fuse locations depend on the vehicle and are outlined on a label on the BCA cover. For an example see See Fig..

Fig. 2, Example Fuse Labeling on BCA Cover

The power supplied by the batteries goes to the electric vehicle distribution module (EVDM) and the signal detect and actuation (SAM) module.

The EVDM is a fuse and relay power distribution box. It provides power and circuit protection for powertrain needs, cab functions, and various stand alone modules. It also supplies power to the emergency power supply circuits in the event of a module failure.

Depending on a vehicle's specifications, the fuses and relays installed and their locations can vary. Each EVDM cover is illustrated with an image of the fuse and relay layout for that vehicle. See Fig. for an example of EVDM cover map of fuses and relays.

Fig. 3, EVDM Inside Cover Map of Fuses and Relays

Both the EVDM and the SAM are grounded at the cab-side front wall.