Operation CHARM: Car repair manuals for everyone.
Home >> Dodge and Ram >> 2012 >> RAM 2500 Truck 4WD L6-6.7L DSL Turbo High Output >> Repair and Diagnosis >> Instrument Panel, Gauges and Warning Indicators >> Instrument Cluster / Carrier >> Description and Operation >> Instrument Cluster - Description

Instrument Cluster - Description






DESCRIPTION





The instrument cluster (2) is located in the instrument panel (1) above the steering column opening and includes the hardware and software necessary to serve as the electronic body control module also known as the Cab Compartment Node (CCN). The remainder of the instrument cluster, including the mounts and the electrical connections, are concealed within the instrument panel behind the cluster bezel. Besides analog gauges and indicators, the CCN module incorporates a single unit for displaying odometer/trip odometer information, engine hours, several warning or reminder indications and certain diagnostic information. The instrument cluster for this vehicle also.





The instrument cluster gauges and indicators are visible through a dedicated opening in the cluster bezel on the instrument panel and are protected by a clear plastic cluster lens that is integral to a cluster lens and hood unit (2). Just behind the cluster lens is the cluster hood. The cluster hood serves as a visor and shields the face of the cluster from ambient light and reflections to reduce glare. A black plastic odometer/trip odometer switch button protrudes through dedicated holes in the cluster lens, located near the lower edge of the cluster just to the left of the speedometer. The molded plastic lens and hood unit has three integral mounting tabs, one each on the lower outboard corners and one on the upper center of the unit. These mounting tabs are used to secure the CCN to the molded plastic instrument panel cluster carrier with three screws.

The rear of the cluster housing and the CCN electronic circuitry are protected by a molded plastic rear cover (1), which is secured to the cluster housing with molded plastic clips, while eight similar clips around the outside perimeter of the rear cover secure it to the cluster lens and hood unit. The rear cover includes clearance holes for the cluster connector receptacles. The connector receptacles on the back of the cluster electronic circuit board connect the CCN to the vehicle electrical system through three take outs with connectors from the instrument panel wire harness.

Sandwiched between the rear cover and the lens and hood unit is the cluster housing (3). The molded plastic cluster housing serves as the carrier for the cluster circuit board and circuitry, the cluster connector receptacles, the gauges, a Light Emitting Diode (LED) for each cluster indicator, an audible tone transducer, the cluster overlay, the gauge pointers, the odometer/trip odometer switch.

The cluster overlay is a laminated plastic unit. The dark, visible, outer surface of the overlay is marked with all of the gauge dial faces and graduations, but this layer is also translucent. The darkness of this outer layer prevents the cluster from appearing cluttered or busy by concealing the cluster indicators that are not illuminated, while the translucence of this layer allows those indicators and icons that are illuminated to be readily visible. The underlying layer of the overlay is opaque and allows light from the LED for each of the various indicators and the LED general illumination behind it to be visible through the outer layer of the overlay only through predetermined stencil-like cutouts. A rectangular opening in the overlay between the Tachometer and the Speedometer through which the Liquid Crystal Display (LCD) unit can be viewed.

Several versions of the CCN module are offered on this vehicle. These versions accommodate all of the variations of optional equipment and regulatory requirements for the various markets in which the vehicle will be offered. The microprocessor-based CCN utilizes integrated circuitry and information carried on the Controller Area Network (CAN) data bus along with several hard-wired analog and multiplexed inputs to monitor sensors and switches throughout the vehicle. In response to those inputs, the internal circuitry and programming of the CCN allow it to control and integrate many electronic functions and features of the vehicle through both hard-wired outputs and the transmission of electronic message outputs to other electronic modules in the vehicle over the CAN data bus. Communication - Description.

VEHICLE SYSTEM SUPPORT

Besides typical instrument cluster gauge and indicator support, the electronic functions and features that the CCN supports or controls include the following:

- Audible Warnings - The CCN electronic circuit board is equipped with an audible tone transducer and programming that allows it to provide various audible alerts to the vehicle operator, including chime tones and beep tones and, emulates the sound of a conventional turn signal or hazard warning flasher. Chime/Buzzer - Description.
- Brake Lamp Control - The CCN provides electronic brake lamp request messages to the Totally Integrated Power Module (TIPM) located in the engine compartment near the battery for brake lamp control, excluding control of the Center High Mounted Stop Lamp (CHMSL), which remains controlled by a direct hard-wired output of the brake lamp switch.
- Cargo Lamp Control - The CCN provides direct control of cargo lamp operation with a load shedding (battery saver) feature which will automatically turn OFF the cargo lamp if it remains ON after a timed interval.
- Electronic Transfer Case Interface - On vehicles equipped with an electronic four-wheel drive transfer case, the CCN monitors a hard-wired multiplex input from the transfer case mode switch and then provides the appropriate electronic data bus messages to the TIPM for transfer case control. After the transfer case shift is completed, the TIPM provides an electronic message back to the CCN and the CCN responds by activating the appropriate 4WD indicators within the cluster or in the transfer case switch.
- Electronic Vehicle Information Center Support - The CCN provides support for the optional Electronic Vehicle Information Center (EVIC) by calculating average fuel economy, distance to empty and outside temperature values and storing trip odometer and elapsed ignition-ON time data.
- Enhanced Accident Response Support - The CCN monitors an input from the Occupant Restraint Controller (ORC) and, following an airbag deployment. The CCN monitors an input from the Powertrain Control Module (PCM) to automatically turn ON the interior lighting after an airbag deployment event, 10 seconds after the vehicle speed is zero. The interior lighting remains illuminated until the ignition switch is turned to the OFF position, at which time the interior lighting returns to normal operation and control. These Enhanced Accident Response System (EARS) features are each dependent upon a functional vehicle electrical system following the vehicle impact event.
- Exterior Lighting Control - The CCN provides electronic head lamp and park lamp request messages to the TIPM for the appropriate exterior lamp control of standard head and park lamps, as well as optional front fog lamps. This includes support for headlamp beam selection and the optical horn feature, also known as flash-to-pass.
- Exterior Lighting Fail-Safe - In the absence of a headlamp switch input, the CCN will turn ON the cluster general illumination lamps and provide electronic headlamp low beam and park lamp request messages to the TIPM for default exterior lamp operation. The TIPM will also provide default park lamp and headlamp low beam operation and the CCN will turn ON the cluster general illumination lighting at full intensity if there is a failure of the electronic data bus communication between the CCN and the TIPM.
- Fuel Level Data Support - The TIPM provides a current source for and receives a Bus message input from the fuel level sending unit located on the fuel pump module in the fuel tank. The TIPM then sends electronic messages to the CCN over the Can Data bus to calculate the proper fuel gauge needle position and low fuel indicator operation. Based upon this input, the CCN also calculates fuel level, average fuel economy and distance to empty data, then uses electronic messaging to transmit this data over the CAN data bus for use by other electronic modules in the vehicle.
- Heated Seat Control - The CCN monitors inputs from the ignition switch and electronic engine speed messages from the Powertrain Control Module (PCM) to control a high side driver output to the heated seat switch Light Emitting Diode (LED) indicators. This input allows the heated seat switches to wake up the heated seat module if the switch is actuated. The CCN will de-energize the heated seat switch LED indicators, which deactivates the heated seat system, if the ignition switch is turned to any position except ON or START, or if the engine speed message indicates zero. Heated Seats - Description.
- Horn Control - The CCN monitors an input from the horn switch and provides electronic horn request messages to the TIPM for horn control.
- Instrument Panel Synchronization - The CCN monitors hard-wired multiplexed inputs from the headlamp switch on the instrument panel, then transmits electronic panel lamp dimming level messages which allows all other electronic modules on the CAN data bus to coordinate their illumination intensity with that of the CCN. This includes a PARADE mode (also known as funeral mode) that allows all LCD units in the vehicle to be illuminated at full (daytime) intensity while driving during daylight hours with the exterior lamps turned ON.
- Interior Lamp Load Shedding - The CCN provides a battery saver feature which will automatically turn OFF all interior lamps and the cargo lamps if they remain ON after a timed interval of about five minutes.
- Interior Lighting Control - The CCN monitors inputs from the interior lighting switch, the door ajar switches, the cargo lamp switch, the reading lamp switches, and the Wireless Ignition Node (WIN) to provide courtesy lamp control. This includes support for timed illuminated entry with theater-style fade-to-OFF and courtesy illumination DEFEAT features.
- Panel Lamps Dimming Control - The CCN monitors hard-wired multiplexed inputs from the headlamp switch on the instrument panel, then provides a hard-wired 12-volt Pulse-Width Modulated (PWM) output that synchronizes the dimming level of all panel lamps dimmer controlled lamps with that of the cluster illumination lamps.
- Remote Keyless Entry - The CCN supports the optional Remote Keyless Entry (RKE) system features, including support for the RKE LOCK, UNLOCK (with optional driver-door-only unlock, and unlock-all-doors), PANIC, audible chirp, optical chirp, illuminated entry modes, an RKE programming mode, as well as optional Vehicle Theft Security System (VTSS) arming (when the proper VTSS arming conditions are met) and disarming.
- Remote Radio Switch Interface - The CCN monitors inputs from the optional remote radio switches and then provides the appropriate electronic data bus messages to the radio to select the radio or optional hands-free cellular system operating mode, volume control, preset station scan and station seek features.
- Turn Signal and Hazard Warning Lamp Control - The CCN monitors hard wired multiplexed inputs from the multi-function switch on the steering column, then provides electronic turn and hazard lamp request messages to the TIPM for turn and hazard lamp control. The CCN also provides an audible click at one of two rates to emulate normal and bulb out turn or hazard flasher operation based upon electronic lamp outage messages from the TIPM, and provides an audible turn signal ON chime warning if a turn is signalled continuously for more than about 1.6 kilometers (one mile) and the vehicle speed remains greater than about 24 kilometers-per-hour (15 miles-per-hour).
- Vehicle Theft Security System Control - The CCN monitors inputs from the door ajar switches, the ignition switch, and the WIN, then provides electronic horn and lighting request messages to the TIPM for the appropriate VTSS alarm output features.
- Wiper and Washer System Control - The CCN monitors LIN Bus inputs from the wiper and washer switches in the multi-function switch on the steering column, then provides electronic wiper and washer request messages to the TIPM for the appropriate wiper and washer system features. Wipers And Washers - Description.

LIQUID CRYSTAL DISPLAY




Figure 3 - SLT Cluster (Gasoline and Diesel)



Figure 4 - HEV Cluster



Figure 5 - SL Cluster (Gasoline Only)
The instrument cluster includes the following Liquid Crystal Display (LCD) units:

- EVIC Display (20)
- Odometer/Trip Odometer Display (20)

An odometer and trip odometer are standard factory-installed equipment in all instrument clusters. The odometer, trip odometer, and engine hours information are displayed in a common electronic, blue-green LCD unit. This LCD unit is soldered onto the cluster electronic circuit board and is visible through a window with a smoked lens located on the lower edge of the speedometer gauge dial face of the cluster overlay. The dark lens over the LCD prevents the indicator from being clearly visible when it is not illuminated.

The odometer, trip odometer, and engine hours information are not displayed simultaneously. The trip odometer reset switch on the instrument cluster circuit board toggles the display between odometer and trip odometer modes by depressing the odometer/trip odometer switch button that extends through the lower edge of the cluster lens, just left of the tachometer. When the trip odometer information is displayed, the word TRIP is also illuminated in the lower right corner of the LCD in a blue-green color and at the same lighting level as the trip odometer information. The engine hours information replaces the selected odometer or trip odometer information whenever the ignition switch is in the ON position and the engine is not running.

The odometer, trip odometer, and engine hours information is stored in the instrument cluster memory. This information can be increased when the proper inputs are provided to the instrument cluster, but the information cannot be decreased. The odometer can display values up to 999,999 kilometers (621,000 miles). The odometer latches at these values, and will not roll over to zero. The trip odometer can display values up to 999.9 kilometers (621,000 miles) before it rolls over to zero. Engine hours are displayed in the format, hr 9999. The cluster will accumulate values up to 65,000 hours before the display rolls over to zero. The engine hours are displayed within the LCD odometer display on low line models and in the EVIC display on high line models.

The odometer display does not have a decimal point and will not show values less than a full unit (kilometer or mile), while the trip odometer display does have a decimal point and will show tenths of a unit (kilometer or mile). The unit of measure (kilometers or miles) for the odometer and trip odometer display is not shown in the LCD. The unit of measure for the instrument cluster odometer/trip odometer is selected at the time that it is manufactured, and cannot be changed. The odometer also has a RENTAL CAR mode, which will illuminate the odometer information in the LCD whenever the driver side front door is opened with the ignition switch in the OFF or ACCESSORY positions.

During daylight hours (exterior lamps are OFF) the odometer LCD is illuminated at full brightness for clear visibility. At night (exterior lamps are ON), the LCD lighting level is adjusted with the other cluster general illumination lamps using the panel lamps dimmer thumbwheel on the headlamp switch. However, a PARADE mode position of the panel lamps dimmer thumbwheel allows the LCD to be illuminated at full brightness if the exterior lamps are turned ON during daylight hours.

The odometer/trip odometer LCD, the trip odometer switch, and the trip odometer switch button are serviced as a unit with the instrument cluster.

The CCN module for this vehicle is serviced only as a complete unit. The CCN module cannot be adjusted or repaired. If a gauge, an LED indicator, the LCD unit, the electronic circuit board, the circuit board hardware, the cluster overlay, or the CCN housing are damaged or ineffective, the entire CCN module must be replaced. The cluster lens, hood and mask unit are available for separate service replacement.

pro multis · About Operation CHARM