Dashboard / Instrument Panel: Description and Operation
INSTRUMENT PANEL SYSTEMDESCRIPTION
Fig. 1:
The instrument panel (Fig. 1) is located at the front of the passenger compartment. This instrument panel uses a full-width structural plastic foundation as its primary support. This foundation structure is often referred to as a structural duct, as the unit also serves as the air duct for the heating and air conditioning system panel outlets, which greatly reduces the number of components used over conventional instrument panel construction. The instrument cluster, radio, A/C-heater control, passenger airbag, headlamp and accessory switches, as well as numerous other components are secured to and supported by this structural duct. The top of the instrument panel structural duct is secured to the top of the dash panel near the base of the windshield using a combination of weld-studs with nuts and screws. A stamped metal end bracket integral to each end of the structural duct is secured to each cowl side inner panel below the instrument panel with a screw. Another stamped metal bracket supports the center of the structural duct by securing it to the top of the floor panel transmission tunnel below the instrument panel with screws.
The instrument panel for this vehicle includes the following major components:
- Accessory Switch Bezel - This molded plastic switch bezel is secured with screws to the structural duct and is visible through a dedicated opening near the bottom of the instrument panel center bezel, below the heater and air conditioner controls.
- Cluster Bezel - This molded plastic bezel is secured with snap clips and screws to the instrument panel structural duct. It trims out the eyebrow over the instrument cluster and center bezel areas of the instrument panel and includes dedicated openings for the instrument cluster, the headlamp switch knob, and the steering column. It also includes a molded rubber sight shield that fills the opening between the instrument cluster and the steering column opening cover, where the steering column passes through the instrument panel.
- Glove Box - The glove box is located on the lower passenger side of the instrument panel. It is comprised of several molded plastic components that are assembled with screws, including; a storage bin, an inner door, a hinge, a latch, and an outer door. The glove box door is specially designed and reinforced to serve as a knee blocker for the front seat passenger.
- Center Bezel - The molded plastic center bezel is secured to the instrument panel structural duct with snap clips. This component, which trims and defines the center stack area of the instrument panel houses the two A/C-heater center panel outlets and includes dedicated openings for the radio, A/C-heater control, and the accessory switch bezel.
- End Cap - A molded plastic end cap is secured with screws to each end of the instrument panel structural duct. Each of these trim pieces also houses an A/C-heater panel outlet and incorporates a side window demister outlet.
- Knee Blocker - This stamped metal reinforcement is concealed behind the steering column opening cover below the steering column and is secured to the instrument panel structural duct with screws.
- Steering Column Opening Cover - The steering column opening cover trims the opening below the steering column in the instrument panel and is secured to the structural duct with snap clips and screws.
- Top Cover - This molded plastic unit forms the hood projection over the instrument cluster and center stack areas of the instrument panel, incorporates the windshield defroster outlet, and trims the top of the instrument panel up to the base of the windshield. It is secured to the instrument panel structural duct with snap clips. Hard wired circuitry connects the electrical components on the instrument panel to each other through the electrical system of the vehicle. These hard wired circuits are integral to several wire harnesses, which are routed throughout the vehicle and retained by many different methods. These circuits may be connected to each other, to the vehicle electrical system and to the instrument panel components through the use of a combination of soldered splices, splice block connectors and many different types of wire harness terminal connectors and insulators. The wiring information includes complete circuit diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pinout and location views for the various wire harness connectors, splices, and grounds.
The service information found here covers the major instrument panel components. However, complete service information for all of the systems and components housed in the instrument panel in a single area of the service manual would not be practical. Therefore, the coverage for any component mounted on or in the instrument panel and not found here, will be found with the service information covering the vehicle system to which the component belongs. The instrument panel structural duct with end brackets is serviced only as a complete unit. If it is faulty or damaged, the entire structural duct unit must be replaced. Most other trim and functional components of the instrument panel are available for service replacement separately from the structural duct.
OPERATION
The instrument panel serves as the command center of the vehicle, which necessarily makes it a very complex unit. The instrument panel is designed to house the controls and monitors for standard and optional powertrains, climate control systems, audio systems, lighting systems, safety systems and many other comfort or convenience items. When the two primary molded plastic components of the instrument panel structural duct are vibration welded together they provide superior instrument panel stiffness and integrity to help reduce buzzes, squeaks, and rattles. This type of construction also provides improved energy absorption which, in conjunction with the dual airbags and seat belts, helps to improve occupant protection.
The instrument panel is also designed so that all of the various controls can be safely reached and the monitors can be easily viewed by the vehicle operator when driving, while still allowing relative ease of access to each of these items for service. Modular instrument panel construction allows all of the gauges and controls to be serviced from the front of the panel. In addition, most of the instrument panel electrical components can be accessed without complete instrument panel removal. However, if necessary, the instrument panel can be removed from the vehicle as an assembly.
The steering column opening cover and knee blocker on the driver side of the instrument panel works in conjunction with the airbag system in a frontal vehicle impact to keep the driver properly positioned for an airbag deployment. In addition, removal of these components provides access to the steering column mounts, the steering column wiring, the headlamp switch, the electronic combination flasher, and much of the instrument panel wiring. In a frontal collision, the glove box door on the passenger side of the instrument panel provides the same function for the front seat passenger as the knee blocker does for the driver. The glove box door also incorporates a recessed latch handle with a lockable latch. Removal of the glove box provides access to the heating and air conditioning electrical and vacuum harnesses, the blower motor relay, the radio antenna coaxial cable, the lower passenger airbag mounts, and additional instrument panel wiring.
Removal of the instrument panel center bezel allows access to the radio, the heating and air conditioning control, and the accessory switch bezel. The accessory switch bezel provides dedicated mounting locations for the cigar lighter, the accessory power outlet, the rear wiper and washer switch, and a rear window defogger switch. Removal of the instrument cluster bezel allows access to the instrument cluster.Removal of the instrument cluster allows access to the cluster illumination and indicator lamp bulbs, and more of the instrument panel wiring. Removal of the instrument panel top cover allows access to the upper passenger airbag mounts. Complete instrument panel removal is required for service of most internal components of the heating and air conditioning system housing, including the heater core and the evaporator.
See the owner's manual in the vehicle glove box for more information on the features, use and operation of all of the components and systems mounted on or in the instrument panel.