Power Distribution Module: Description and Operation
POWER DISTRIBUTION SYSTEMThis covers the various standard and optional power distribution components used on this model.
The power distribution system for this vehicle is designed to provide safe, reliable, centralized and convenient to access distribution of the electrical current required to operate all of the many standard and optional factory Installed electrical and electronic powertrain, chassis, safety, comfort and convenience systems. At the same time, these systems were designed to provide centralized locations for conducting diagnosis of faulty circuits, and for sourcing the additional current requirements of many aftermarket vehicle accessory and convenience items.
These power distribution systems also incorporate various types of circuit control and protection features, including:
- Fuses
- Fuse cartridges
- Fusible links
- Automatic resetting circuit breakers
- Relays
- Flashers
- Timers
Circuit splice blocks.
The power distribution system for this vehicle consists of the following components:
- Power Distribution Center (PDC)
- Junction Block (JB)
- Accessory power outlet.
Following are general descriptions of the major components in the power distribution system. Refer to the owner's manual in the vehicle glove box for more information on the features, use and operation of all of the power distribution system components.
POWER DISTRIBUTION CENTER (PDC)
Power Distribution Center (PDC):
All of the electrical current distributed throughout this vehicle is directed through the standard equipment Power Distribution Center (PDC). The molded plastic PDC housing is located in the left front corner of the engine compartment, just behind the battery. The PDC housing has a molded plastic cover that includes an integral hinge feature on the inboard side, and an integral latch on the outboard side. The PDC cover is easily removed for service access and has a convenient fuse and relay layout label affixed to the inside surface of the cover to ensure proper component identification.
The PDC housing is secured in the engine compartment on the left front corner with three screws to the transmission and engine control module bracket. A small red molded plastic protective cover on the top near the rear of the PDC is unsnapped to access the battery/generator cable input connection stud. All of the PDC outputs are through the integral engine compartment wire harness, which exits from the rear of the PDC housing.
All of the current from the battery/generator cable connection enters the PDC through a 140 ampere fusible link that is secured to the top of the PDC housing. The PDC houses up to ten maxi-fuse cartridges, which replace all in-line fusible links. The PDC also houses up to eight blade-type fuses, up to four full International Standards Organization (ISO) relays, and up to eight ISO micro-relays. Internal connection of all the PDC circuits is accomplished by an intricate network of hard wiring and bus bars.
The fusible link, fuse cartridges, fuses and relays are available for service replacement. The PDC unit cannot be repaired and is only serviced as a unit with the engine compartment wire harness. If the PDC is faulty or damaged, the engine compartment wire harness assembly must be replaced.
JUNCTION BLOCK (JB)
Junction Block Location:
An electrical Junction Block (JB) is located in the left endcap of the instrument panel. The JB combines the functions previously provided by a separate fuseblock module and relay center. It also serves to simplify and centralize numerous electrical components, as well as to distribute electrical current to many of the accessory systems in the vehicle. It eliminates the need for numerous splice connections and serves in place of a bulkhead connector between many of the engine compartment, instrument panel, and body wire harnesses.
The JB is positioned on a mounting bracket up and under the left instrument panel. It is secured by three screws. The JB is concealed behind the left instrument panel endcap. The left instrument panel endcap is a snap-fit fuse access cover that conceals the JB fuses. A fuse puller and spare fuse holders are located on the back of the endcap, as well as the fuse layout to ensure proper fuse identification. The left instrument panel endcap must be removed to access components other than the fuses in the JB.
All of the current entering and leaving the JB does so through wire harnesses, which are connected to the JB through integral connector receptacles molded into the JB housing. The JB houses blade-type fuses, blade-type automatic resetting circuit breakers, full International Standards Organization (ISO) relays, and ISO micro-relays. Internal connection of all the JB circuits is accomplished by an intricate network of hard wiring and bus bars.
The fuses, circuit breakers, relays, and are available for service replacement. The JB unit cannot be repaired and is only serviced as an assembly. If any internal circuit or the JB housing is faulty or damaged, the entire Junction Block assembly must be replaced.