Power and Ground Distribution: Description and Operation
POWER DISTRIBUTIONThis group covers the various standard and optional power distribution components used on this model. Refer to Wiring Diagrams for complete circuit diagrams of the various power distribution components.
The power distribution system for this vehicle consists of the following components:
- Power Distribution Center (PDC)
- Fuse Block
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.
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.
CIGAR LIGHTER/POWER OUTLET
Fig. 1 Instrument Panel Mounted Cigar Lighter/Power Outlet Location:
Instrument Panel Mounted
An instrument panel mounted cigar lighter/power outlet receptacle (Fig. 1) is optional equipment on this model. On models equipped with the optional Smoker's Package, the cigar lighter knob and heating element are included. On models without the Smoker's Package, the cigar lighter receptacle is equipped with a snap fit plastic cap and is treated as an auxiliary power outlet. The cigar lighter receptacle is installed in the instrument panel accessory switch bezel, which is located near the bottom of the instrument panel center stack area, below the radio. The cigar lighter base is secured by a snap fit within the center lower bezel. This power outlet has a constant 12 volt battery feed.
The cigar lighter receptacle is serviced with the accessory switch bezel and if defective, the entire switch bezel must be replaced. The plastic cap and the knob and heating element unit are available for service replacement. These components cannot be repaired and, if faulty or damaged, they must be replaced.
Fig. 2 Console Mounted Power Outlet Location:
Fig. 3 Rear Cargo Area Power Outlet Location:
Front Console And Rear Cargo Mounted
A front console mounted power outlet is standard equipment and a rear cargo area power outlet is optional equipment on this model. The front console mounted power outlet is mounted near the front of the console just in front of the cup holders (Fig. 2). This outlet can be used as a cigar lighter or power outlet, but only has 12 volt battery voltage when the ignition is in the ON or ACC positions. The rear power outlet is installed in the right rear quarter trim panel, near the spare tire jack (Fig. 3). The power outlet base and mount are secured by a snap fit within the quarter trim panel. A plastic protective cap snaps into the power outlet base when the power outlet is not being used, and hangs from the power outlet base mount by an integral bail strap while the power outlet is in use. While the power outlet is very similar to a cigar lighter base unit, it does not include the two small spring-clip retainers inside the bottom of the receptacle shell that are used to secure the cigar lighter heating element to the insulated contact. It has 12 volt battery voltage when the ignition is in the ON or ACC positions.
Cigar Lighter/power Outlet (instrument Panel And Console Mounted)
The cigar lighter consists of two major components: a knob and heating element unit, and the cigar lighter base or receptacle shell. The receptacle shell is connected to ground, and an insulated contact in the bottom of the shell is connected to battery current.
The cigar lighter knob and heating element are encased within a spring-loaded housing, which also features a sliding protective heat shield. When the knob and heating element are inserted in the receptacle shell, the heating element resistor coil is grounded through its housing to the receptacle shell. If the cigar lighter knob is pushed inward, the heat shield slides up toward the knob exposing the heating element, and the heating element extends from the housing toward the insulated contact in the bottom of the receptacle shell.
Two small spring-clip retainers are located on either side of the insulated contact inside the bottom of the receptacle shell. These clips engage and hold the heating element against the insulated contact long enough for the resistor coil to heat up. When the heating element is engaged with the contact, battery current can flow through the resistor coil to ground, causing the resistor coil to heat.
When the resistor coil becomes sufficiently heated, excess heat radiates from the heating element causing the spring-clips to expand. Once the spring-clips expand far enough to release the heating element, the spring-loaded housing forces the knob and heating element to pop back outward to their relaxed position. When the cigar lighter knob and element are pulled out of the receptacle shell, the protective heat shield slides downward on the housing so that the heating element is recessed and shielded around its circumference for safety.
Power Outlet (rear Cargo Area Mounted)
The power outlet base or receptacle shell is connected to ground, and an insulated contact in the bottom of the shell is connected to battery current. The power outlet receives battery voltage from a fuse in the Power Distribution Center (PDC) through a fuse in the fuse block when the ignition is in the ON or ACC positions.
Fig. 6 Fuse Block Location:
FUSE BLOCK
An electrical Fuse Block is located in the left front lower instrument panel (Fig. 6). It serves to simplify and centralize numerous electrical components, as well as to distribute electrical current to many of the accessory systems in the vehicle.
The Fuse Block is positioned on a mounting bracket up and under the left instrument panel. It is secured by two screws. The fuse block is concealed behind a fuse panel cover. The fuse panel cover is a snap-fit access cover that conceals the fuse block fuses. A fuse layout placard is on the back of the end cap to ensure proper fuse identification.
The fuse block houses blade-type fuses and automatic resetting circuit breakers. Internal connection of all the fuse block circuits is accomplished by an intricate network of hard wiring and bus bars. Refer to Wiring Diagrams for complete circuit diagrams.
The fuses and circuit breakers are available for service replacement. The fuse block unit cannot be repaired and is only serviced as an assembly. If any circuit or the fuse block housing is faulty or damaged, the entire fuse block and instrument panel wire harness assembly must be replaced.
IOD FUSE
All vehicles are equipped with an Ignition-Off Draw (IOD) fuse that is disconnected within the Power Distribution Center (PDC) when the vehicle is shipped from the factory. Dealer personnel are to reconnect the IOD fuse in the PDC as part of the preparation procedures performed just prior to new vehicle delivery.
The term ignition-off draw identifies a normal condition where power is being drained from the battery with the ignition switch in the OFF position. The IOD fuse feeds the memory and sleep mode functions for some of the electronic modules in the vehicle as well as various other accessories that require battery current when the ignition switch is in the OFF position, including the clock. The only reason the IOD fuse is disconnected is to reduce the normal IOD of the vehicle electrical system during new vehicle transportation and pre-delivery storage to reduce battery depletion, while still allowing vehicle operation so that the vehicle can be loaded, unloaded and moved as needed by both vehicle transportation company and dealer personnel.
The IOD fuse is disconnected from PDC fuse cavity 18 when the vehicle is shipped from the assembly plant. Dealer personnel must reconnect the IOD fuse when the vehicle is being prepared for delivery in order to restore full electrical system operation. Once the vehicle is prepared for delivery, the IOD function of this fuse becomes transparent and the fuse that has been assigned the IOD designation becomes only another Fused B(+) circuit fuse. The IOD fuse serves no useful purpose to the dealer technician in the service or diagnosis of any vehicle system or condition, other than the same purpose as that of any other standard circuit protection device.
The IOD fuse can be used by the vehicle owner as a convenient means of reducing battery depletion when a vehicle is to be stored for periods not to exceed about thirty days. However, it must be remembered that disconnecting the IOD fuse will not eliminate IOD, but only reduce this normal condition. If a vehicle will be stored for more than about thirty days, the battery negative cable should be disconnected to eliminate normal IOD; and, the battery should be tested and recharged at regular intervals during the vehicle storage period to prevent the battery from becoming discharged or damaged. Refer to Battery for the location of additional service information covering the battery.
Fig. 7 Power Distribution Center (PDC) Location:
POWER DISTRIBUTION CENTER
All of the electrical current distributed throughout this vehicle is directed through the standard equipment Power Distribution Center (PDC) (Fig. 7). The molded plastic PDC housing is located in the left front corner of the engine compartment, just behind the air cleaner housing and the battery. The PDC housing has a molded plastic cover. 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 to the left inner fender well an indexing pin and one screw. All of the PDC outputs are through the integral engine compartment wire harness.
All of the current from the generator cable connection goes to the battery through a 10 gauge fusible link that is secured with a nut to the positive battery terminal at the starter. The PDC houses up to ten six fuse cartridges, which replace all in-line fusible links. The PDC also houses up to twelve blade-type fuses, up to two full International Standards Organization (ISO) relays, and up to eight mini International Standards Organization (ISO) relays. Internal connection of all the PDC circuits is accomplished by an intricate network of hard wiring and bus bars. Refer to Wiring Diagrams for complete circuit diagrams.
The fusible link, 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.