Component Description
ACCESSORY RELAYThe accessory relay is an electromechanical device that switches fused battery current to the accessory powered vehicle circuits when the ignition switch is turned to the Accessory or ON positions. The delay feature will maintain power to the accessories for 45 seconds after the ignition is shut OFF or until a door is opened. This allows sufficient time to close windows and park the windshield wipers. The accessory relay is located in the Integrated Power Module (IPM) in the engine compartment.
The accessory relay is a International Standards Organization (ISO) relay. Relays conforming to the ISO specifications have common physical dimensions, current capacities, terminal patterns, and terminal functions.
The accessory relay cannot be repaired or adjusted and, if faulty or damaged, it must be replaced.
The ISO relay consists of an electromagnetic coil, a resistor or diode, and three (two fixed and one movable) electrical contacts. The movable (common feed) relay contact is held against one of the fixed contacts (normally closed) by spring pressure. When the electromagnetic coil is energized, it draws the movable contact away from the normally closed fixed contact, and holds it against the other (normally open) fixed contact.
When the electromagnetic coil is de-energized, spring pressure returns the movable contact to the normally closed position. The resistor or diode is connected in parallel with the electromagnetic coil in the relay, and helps to dissipate voltage spikes that are produced when the coil is de-energized.
Fig.2 Battery Thermal Guard:
INTEGRATED POWER MODULE
The Integrated Power Module (IPM) is a combination of the Power Distribution Center (PDC) and the Front Control Module (FCM). The IPM is located in the engine compartment, next to the battery on this model (Fig. 2). The power distribution center mates directly with the Front Control Module (FCM) to form the IPM Fuse and Relay Center. The power distribution center (PDC) is a printed circuit board based module that contains fuses and relays, while the front control module contains the electronics controlling the IPM and other functions. This IPM connects directly to the battery positive via a four pin connector. The ground connection is via two other connectors. The IPM provides the primary means of voltage distribution and protection for the entire vehicle.
The molded plastic IPM housing includes a base and cover. The IPM cover is easily opened or removed for service access by squeezing the two marked cover latches and has a fuse and relay layout map integral to the inside surface of the cover. This IPM housing base and cover are secured in place by an IPM mounting bracket. This mounting bracket is designed to allow the IPM to rotate counter-clockwise once the locking tab is disengaged. The IPM mounting bracket is secured in place by bolts threaded into the left front wheel house.
Replaceable components of the IPM assembly are broken down into the following components: the Power Distribution Center (PDC) (without fuses or relays), the IPM cover, the Front Control Module (FCM), the IPM mounting bracket, IPM bracket retaining clips and the IPM assembly which includes the power distribution center, the cover and FCM.
Refer to the Front Control Module in the Electronic Control Module section of this service manual for information on the FCM.
All of the current from the battery and the generator output enters the Integrated Power Module (IPM) via a four-pin connector on the bottom of the module. The IPM cover is unlatched and opened or removed to access the fuses or relays. Internal connections of all of the power distribution center circuits is accomplished by a combination of bus bars and a printed circuit board. Refer to the Wiring section of the service manual for complete IPM circuit schematics.
IOD FUSE
All vehicles are equipped with an Ignition-Off Draw (IOD) fuse that is removed from its normal cavity in the Integrated Power Module (IPM) when the vehicle is shipped from the factory Dealer personnel are to remove the IOD fuse from the storage location and install it into the IPM fuse cavity marked IOD as part of the preparation procedures performed just prior to new vehicle delivery.
The IPM has a molded plastic cover that can be removed to provide service access to all of the fuses and relays in the IPM. An integral latch and hinges are molded into the IPM cover for easy removal. A fuse layout map is integral to the underside of the IPM cover to ensure proper fuse and relay identification. The IOD fuse is a 15 ampere blade-type cartridge fuse and, when removed, it is stored in a fuse cavity adjacent to the washer fuse within the IPM.
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 removed 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 removed from the IPM fuse cavity when the vehicle is shipped from the assembly plant. Dealer personnel must install 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 removing 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 System for additional service information.
POWER OUTLET
Accessory power outlets are standard equipment on this model Two power outlets are installed in the instrument panel center lower bezel, which is located near the bottom of the instrument panel center stack area. Two additional power outlets are also incorporated into the vehicle, one on the left rear C-pillar trim and the other in the center console, if equipped. The power outlets bases are secured by a snap fit in the appropriate bezels. A hinged plug flips closed to conceal and protect the power outlet base when the power outlet is not being used.
The power outlet receptacle unit and the power outlet plugs are each available for service replacement.
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 on the instrument panel marked with a battery receives battery voltage from a fuse in the Integrated Power Module (IPM) at all times. The other power outlet on the instrument panel marked with a key receives battery voltage only when the key is in the ON position.
The power outlet located in the center console receives battery voltage all the time when positioned between the front seats and key-on voltage when positioned between the rear seats. The power outlet located on the C-pillar receives battery voltage only when the key is in the ON position.