Driver/Vehicle Information Display: Description and Operation
OVERHEAD CONSOLEOverhead Console
The overhead console for this model includes two front-mounted reading and courtesy lamps, a storage bin, and either a standard paperclip or an optional compass mini-trip computer, with or without the universal transmitter option.
The overhead console is secured with two snap clips at the rear and a single screw at the front to the overhead console mounting bracket. The front of the overhead console mounting bracket is secured to the roof header near the windshield with two screws, and the rear of the bracket is secured with double-faced tape to the inside surface of the roof panel. A single electrical connection joins the overhead console wire harness to the roof wire harness.
Following are general descriptions of the major components used in the overhead console. See the owner's manual in the vehicle glove box for more information on the use and operation of the various overhead console features.
Storage Bin
A storage bin is included in the overhead console. The storage bin is located near the center of the overhead console and is held in the closed position by a spring-loaded latch mechanism that is integral to the storage bin door. The interior of the bin is lined with a foam rubber padding material to protect the contents from being scratched. A damper spring is snapped onto the pivot shaft of the storage bin door. The damper spring engages two flats on the shaft and is anchored in a slot in the rear flange of the overhead console reading and courtesy lamp housing to provide a smooth opening action and an open detent position for the storage bin unit.
The storage bin and door unit is available for service replacement. The bin and door unit includes the spring-loaded latch mechanism, the bin liner and the damper spring. If any of these components is damaged or faulty, the storage bin and door unit must be replaced.
The storage bin is opened by pressing the latch on the rear edge of the door towards the front of the vehicle, then pulling the bin downward to the open detent position. The spring-loaded latch mechanism on the bin door will automatically engage when the bin is closed. See the owner's manual in the vehicle glove box for more information on the use and operation of the storage bin.
Paperclip
A paperclip is standard equipment on the base version of the overhead console. The paperclip provides a convenient place for storage and easy retrieval of notes, maps, toll tickets or stubs and other paper items that may be required or desired while driving. The paperclip is located near the front of the overhead console and is secured in the overhead console housing by four screws.
The paperclip is available for service replacement, but it cannot be adjusted or repaired. If the paperclip is damaged or faulty it must be replaced.
COMPASS/MINI-TRIP COMPUTER
The compass mini-trip computer is located in the overhead console on models equipped with this option. The compass mini-trip computer units include the electronic control module, a Vacuum-Fluorescent Display (VFD), a compass sensor unit and two push button function switches.
The compass mini-trip computer module contains a central processing unit and interfaces with other electronic modules in the vehicle on the Programmable Communication Interface (J1850) data bus network. The J1850 data bus network allows the sharing of sensor information. This helps to reduce wire harness complexity, reduce internal controller hardware, and reduce component sensor current loads. At the same time, this system provides increased reliability, enhanced diagnostics, and allows the addition of many new feature capabilities.
The compass mini-trip computer provides several electronic functions and features. Some of the functions and features that the compass mini-trip computer module supports and/or controls, include the following display options:
- Compass and temperature - provides the outside temperature and one of eight compass readings to indicate the direction the vehicle is facing.
- Trip odometer (TRIP ODO) - shows the distance travelled since the last trip computer reset.
- Average fuel economy (AVG ECO) - shows the average fuel economy since the last trip computer reset.
- Instant fuel economy (ECO) - shows the present fuel economy based upon the current vehicle distance and fuel used information.
- Distance to empty (DTE) - shows the estimated distance that can be travelled with the fuel remaining in the fuel tank. This estimated distance is computed using the level of the fuel in the tank and a weighted average of long term and recent Average Fuel Economy.
- Elapsed time (ET) - shows the accumulated ignition-ON time since the last trip computer reset.
- Blank screen - the compass mini-trip VFD is turned OFF.
The ambient temperature sensor is hard wired to the HVAC control head. Data input for all other compass mini-trip computer functions, including VFD dimming level, is received through J1850 data bus messages. The compass mini-trip computer uses its internal programming and all of these inputs to calculate and display the requested data. If the data displayed is incorrect, perform the self-diagnostic tests. If these tests prove inconclusive, the use of a DRB scan tool and the proper Diagnostic Procedures are recommended for further testing of the compass mini-trip computer module and the J1850 data bus.
The compass mini-trip computer module cannot be repaired, and is available for service only as a unit. This unit includes the push button switches and the plastic module and display lens. If any of these components is faulty or damaged, the complete compass mini-trip computer module must be replaced.
Compass
While in the compass/temperature mode, the compass will display the direction in which the vehicle is pointed using the eight major compass headings (Examples: north is N, northeast is NE). The self-calibrating compass unit requires no adjusting in normal use. The only calibration that may prove necessary is to drive the vehicle in one or two complete circles, on level ground, in not less than 16 seconds. This will reorient the compass unit to its vehicle.
The compass unit also will compensate for magnetism the body of the vehicle may acquire during normal use. However, avoid placing anything magnetic directly on the roof of the vehicle. Magnetic mounts for an antenna, a repair order hat, or a funeral procession flag can exceed the compensating ability of the compass unit if placed on the roof panel. Magnetic bit drivers used on the fasteners that hold the overhead console assembly to the roof header can also affect compass operation. If the vehicle roof should become magnetized, the demagnetizing and calibration procedures found may be required to restore proper compass operation.
Temperature
The temperature displays the outside ambient temperature in whole degrees. The temperature display can be changed from Fahrenheit to Celsius using the U.S./Metric push button. The displayed temperature is not an instant reading of conditions, but an average temperature. It may take the temperature display several minutes to respond to a major temperature change, such as driving out of a heated garage into winter temperatures.
When the ignition switch is turned to the OFF position, the last displayed temperature reading stays in the temperature unit memory. When the ignition switch is turned to the ON position again, the temperature will display the memory temperature if the engine OFF time is less than 90 minutes. If the engine OFF time is more than 90 minutes, the temperature will display the actual temperature sensed by the ambient temperature sensor. The temperature display update interval varies with the vehicle speed.
The temperature function is supported by an ambient temperature sensor. The sensor is mounted outside the passenger compartment near the front and center of the vehicle, and is hard wired to the HVAC control head which sends temperature on J1850 data bus circuit. The ambient temperature sensor is available as a separate service item.
NOTE: The compass mini-trip computer will display min and max temperatures of -40 °C (-40 °F) and 54 °C (130 °F).
The compass mini-trip computer only operates with the ignition switch in the ON position. When the ignition switch is turned to the ON position, all of the segments in the compass mini-trip computer VFD will be turned OFF for one second, then the display will return to the last function being displayed before the ignition was turned to the OFF position. With the ignition switch in the ON position, momentarily depressing and releasing the Step push button switch will cause the compass-mini-trip computer to change its mode of operation, and momentarily depressing and releasing the U.S./Metric push button will cause the unit to toggle between U.S. and Metric measurements.
This compass mini-trip computer features several functions that can be reset. If the RESET push button is depressed for more than one second with the ignition switch in the ON position, the trip computer information that can be reset is reset. However, the reset will only occur if the function currently displayed is a function that can be reset. The functions that can be reset are: TRIP ODO, AVG ECO, and ET. All three of these functions can be reset at once by pressing the RESET button twice within 3 seconds while any one of the three functions is selected.
For more information on the features and control functions of the compass mini-trip computer, see the owner's manual in the vehicle glove box.
Fig. 10 Ambient Temperature Sensor:
AMBIENT TEMP SENSOR
The ambient air temperature sensor is hardwired to the HVAC control and the HVAC control sends out a J1850 message to the overhead console. The ambient temperature sensor is a variable resistor (Fig. 5)mounted to a bracket that is secured with a screw to the right side of the radiator yoke, behind the radiator grille and in front of the engine compartment.
The ambient temperature sensor cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.
The ambient temperature sensor is a variable resistor that operates on a five-volt reference signal sent to it by the HVAC control head unit. The resistance in the sensor changes as temperature changes, changing the temperature sensor signal circuit voltage to the HVAC control head unit. Based upon the resistance in the sensor, the HVAC control head unit senses a specific voltage on the temperature sensor signal circuit, which it is programmed to correspond to a specific temperature.
UNIVERSAL TRANSMITTER
On some models a Universal Transmitter transceiver is standard factory-installed equipment. The universal transmitter transceiver is integral to the overhead console. The only visible component of the universal transmitter are the three transmitter push buttons at the rear of the CMTC. The three universal transmitter push buttons can be easily identified by sight.
Each of the three universal transmitter push buttons controls an independent radio transmitter channel. Each of these three channels can be trained to transmit a different radio frequency signal for the remote operation of garage door openers, motorized gate openers, home or office lighting, security Systems or just about any other device that can be equipped with a radio receiver in the 286 to 399 MegaHertz (MHz) frequency range for remote operation. The universal transmitter is capable of operating systems using either rolling code or non-rolling code technology.
The universal transmitter cannot be repaired, and is available for service only as a unit. This unit includes the push button switches and the plastic module.
The universal transmitter operates on a non-switched source of battery current so the unit will remain functional, regardless of the ignition switch position. For more information on the features, programming procedures and operation of the universal transmitter, see the owner's manual in the vehicle glove box.