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Description The exterior lighting system for the 2011-2013 Grand Cherokee includes the following exterior lamp units:
Hard wired circuitry connects the exterior lighting system components to 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 exterior lighting components through the use of a combination of soldered splices, splice block connectors, and many different types of wire harness terminal connectors and insulators.
Following are paragraphs that briefly describe the operation of each of the major exterior lighting systems. The lamps and the hard wired circuits between components related to the exterior lighting system may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the exterior lighting system or the electronic controls or communication between modules and other devices that provide some features of the exterior lighting system. The most reliable, efficient, and accurate means to diagnose the exterior lighting system or the electronic controls and communication related to exterior lighting system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information. AUTOMATIC HEADLAMPS The automatic headlamp system includes the headlamp switch, the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN), the Totally Integrated Power Module (TIPM), the ignition switch (also known as the Wireless Ignition Node/WIN), the air conditioner - heater control unit and the sun load sensor on the top of the instrument panel. The TIPM energizes the sun load sensor to provide an ambient light level input to the air conditioner - heater control whenever the electronic ignition switch status messages received from the WIN over the Controller Area Network (CAN) data bus indicate the ignition switch ON position is selected. The air conditioner - heater control responds to the sun sensor input by sending the appropriate electronic light level messages back to the TIPM over the CAN data bus. When the A (Automatic) position is selected with the headlamp switch, the EMIC responds to this input by sending an electronic lighting request message to the TIPM over the CAN data bus. With the engine running, the TIPM responds to these messages by automatically controlling a pulse width modulated voltage output to the selected headlamp bulb filaments or electronic ballast units through the right and left low or high beam driver circuits to illuminate the headlamps. The TIPM also remembers which beams (low or high) were selected when the headlamps were last turned OFF, and energizes those beams and lamps again the next time it turns the headlamps ON. BACKUP LAMPS The backup (or reverse) lamps have a path to ground at all times through a takeout and eyelet terminal of the body wire harness that is secured by a ground screw to the body sheet metal. The Powertrain Control Module (PCM) continually monitors a hard wired multiplex input from the Transmission Range Sensor (TRS), then sends the proper electronic transmission gear selector status messages to other electronic modules over the CAN data bus. Whenever the ignition switch is in the ON position and the TIPM receives an electronic message indicating the status of the transmission gear selector is REVERSE, it provides a battery voltage output to the backup lamps on the backup lamp feed circuit. BRAKE LAMPS The brake (or stop) lamps and the Center High Mounted Stop Lamp (CHMSL) each have a path to ground at all times through a takeout and eyelet terminal of the body wire harness that is secured by a ground screw to the body sheet metal within the passenger compartment. The brake lamps and CHMSL receive battery voltage on the brake lamp switch feed circuit when the brake lamp switch is closed by the brake pedal arm. On domestic market vehicles, the TIPM monitors an input from the brake lamp switch, then provides the proper outputs to the brake lamps, while the CHMSL is controlled by a hard wired output from the brake lamp switch. On export market vehicles, the CHMSL and brake lamps are connected to a hard wired output from the brake lamp switch. On vehicles so equipped, the brake lamp function of the trailer tow stop/turn relays is controlled by an output from the TIPM based upon the hard wired input from the brake lamp switch. DAYTIME RUNNING LAMPS - EXCEPT SRT Non-SRT vehicles manufactured for sale in Canada and equipped with halogen headlamps illuminate both low beam headlamp bulbs at a reduced intensity when the engine is running, the parking brake is released, the automatic transmission gear selector is not in the PARK position and the exterior lamps are turned OFF. Under the same conditions, vehicles manufactured for U.S. fleet sales and equipped with halogen headlamps illuminate both high beam headlamp bulbs at a reduced intensity. On non-SRT vehicles equipped with High Intensity Discharge (HID) headlamps regardless of the market, the TIPM operates a dedicated DRL bulb (domestic markets) or a combined position/DRL bulb (export markets) through right and left DRL relays to serve as the DRL. On SRT vehicles regardless of the market destination, a separate DRL lamp unit illuminates multiple Light Emitting Diode (LED) units at a high intensity to serve as the DRL. The TIPM must be programmed appropriately for this feature to be enabled. Once enabled, anytime the TIPM receives electronic messages over the CAN data bus from the Powertrain Control Module (PCM) indicating the engine is running, from the EMIC indicating the status of the headlamp exterior lighting input is OFF or A (Automatic) and indicating that the parking brake is released, it energizes the appropriate bulbs or LED units. On vehicles with halogen headlamps, the TIPM provides a Pulse Width Modulated (PWM) voltage output to illuminate the appropriate headlamp bulbs at the proper intensity. On vehicles with HID headlamps, the TIPM provides a path to ground for the DRL relays to produce DRL illumination at the proper intensity. DAYTIME RUNNING LAMPS - SRT ONLY SRT vehicles regardless of the market destination are equipped with dedicated Daytime Running Lamps (DRL) containing multiple Light Emitting Diode (LED) units. In SRT vehicles manufactured for sale in domestic markets these DRL units also operate in a low intensity mode in conjunction with the park lamps and head lamps to serve as accent lighting. The DRL units in SRT vehicles manufactured for sale in export markets operate only at high intensity to serve as the DRL, and are turned OFF when the front fog lamps are illuminated. The TIPM controls SRT DRL unit illumination at the proper intensity for all markets. FRONT FOG LAMPS Vehicles equipped with optional front fog lamps include a front fog lamp switch integral to the headlamp switch on the instrument panel. The front fog lamps have a path to ground at all times through their connection to the Front End Module (FEM) wire harness. The FEM wire harness has takeouts with eyelet terminals that are secured by ground screws to the body sheet metal within the engine compartment. The EMIC monitors a hard wired multiplex input from the headlamp switch to determine whether the fog lamps are selected, then sends electronic fog lamp switch request messages to the TIPM over the CAN data bus. When the TIPM receives a fog lamp switch request message it then controls front fog lamp operation by providing a battery voltage output to the fog lamps through the right and left front fog lamp control circuits. The TIPM also sends the appropriate electronic message back to the EMIC to illuminate or extinguish the front fog lamp indicator. The TIPM will automatically de-energize the front fog lamps any time the headlamp high beams are selected. The TIPM also provides a battery saver (load shedding) feature for the front fog lamps, which will turn these lamps OFF if they are left ON for more than about eight minutes after the electronic ignition switch status messages from the WIN transition to LOCK, if there is a charging system failure or if the electrical system voltage falls below about 11.75 volts for more than about 30 seconds. Each front fog lamp includes an integral adjustment thumbwheel to be used for static aiming of the fog lamp beams. HAZARD WARNING LAMPS The hazard warning system includes the EMIC, the TIPM and the hazard switch in the switch pod located in the center stack area of the instrument panel, below the air conditioner - heater controls. The TIPM monitors a hard wired input from the hazard switch through an internal pull-up to determine the status of the hazard switch. When the TIPM receives an input from the hazard switch it controls hazard warning system operation and flash rate by controlling a battery voltage outputs through high side drivers on the right and left turn signal feed circuits. The TIPM also sends the appropriate electronic messages back to the EMIC over the CAN data bus to control the illumination and flash rate of the right and left turn signal indicators, as well as to control the click rate of an electromechanical relay soldered onto the EMIC electronic circuit board that emulates the sound emitted by a conventional hazard warning flasher. The EMIC then sends an electronic message to the instrument panel switch pod over the Local Interface Network (LIN) data bus to control the illumination of the hazard switch push button. HEADLAMPS The headlamp system includes the Steering Control Module (SCM), the EMIC and the TIPM, the headlamp switch on the instrument panel and the multi-function switch on the steering column. On vehicles with the optional High Intensity Discharge (HID) headlamps, the HID electronic ballast module of each front lamp unit is also part of the headlamp system. Each halogen headlamp bulb and the HID electronic ballast module has a path to ground at all times through their connection to the FEM wire harness. The FEM wire harness has takeouts with eyelet terminals that are secured by ground screws to the front end sheet metal within the engine compartment. The TIPM will store a Diagnostic Trouble Code (DTC) for any shorts or opens in the headlamp circuits. The EMIC monitors a hard wired multiplex input from the headlamp switch to determine the status of the headlamp switch. The SCM monitors a hard wired multiplex input to determine the status of the multi-function switch and whether the headlamp high or low beams are selected. The SCM then sends the appropriate electronic headlamp beam select switch status messages to the TIPM over the CAN data bus. The EMIC then sends the appropriate electronic headlamp request messages to the TIPM over the CAN data bus. The TIPM responds to these messages by providing a Pulse Width Modulated (PWM) voltage output to the proper halogen headlamp bulbs or a control voltage to the HID electronic ballast modules through high side drivers on the right and left low and high beam feed circuits to illuminate the selected headlamp beams. The TIPM also sends the appropriate electronic messages to the EMIC to control the illumination of the high beam indicator. On vehicles with the optional HID headlamps, the HID electronic ballast module uses a high voltage Alternating Current (AC) output to activate the HID igniter integral to the lighting element to provide a high voltage surge, which creates a light arc between the lighting element electrodes. Once the electronic ballast module detects a suitably stable light arc, it switches over to a power-limiting mode to sustain the light arc. Also an electric motor drives a shutter within each HID lamp unit and the position of the shutter controls whether the low beams (shutter closed) or high beams (shutter open) are illuminated. When the optical horn feature is selected, the low beams will shut OFF about 200 milliseconds after the high beams are activated. The TIPM also remembers which beams (LOW or HIGH) were selected when the headlamps were last turned OFF, and energizes those beams again the next time the headlamps are turned ON. The TIPM provides a battery saver (load shedding) feature for the headlamps, which will turn these lamps OFF if they are left ON for more than about eight minutes after the electronic ignition switch status messages from the WIN transition to LOCK. The EMIC and the TIPM each provide a fail-safe feature for the headlamps, which will cause the TIPM to turn the low beam headlamps ON automatically if there is no input available from the headlamp switch. The TIPM also provides a fail-safe feature for the headlamps that will turn the headlamps ON automatically whenever a loss of CAN bus communication is detected while the electronic ignition switch status messages from the WIN indicate the ignition ON position is selected. Each headlamp includes an integral reflector adjustment screw to be used for static aiming of the headlamps. HEADLAMP DELAY The headlamp delay feature includes the headlamp switch, the EMIC, the WIN and the TIPM. This feature has customer programmable delay intervals of 0 seconds (disabled), 30 seconds, 60 seconds and 90 seconds. If the headlamp switch remains in the headlamp ON position until the electronic ignition switch status messages from the WIN indicate the ignition OFF position is selected, then the headlamps will remain illuminated until after the selected delay interval has elapsed. The park lamps will not stay ON during the headlamp delay interval. The default delay interval is 90 seconds, but can be reprogrammed by the customer using the customer programmable features function of the Electronic Vehicle Information Center (EVIC). HEADLAMP LEVELING On vehicles with the HID headlamps, an automatic leveling system is used that includes front and rear axle sensors and an Automatic Headlamp Leveling Module (AHLM) located on the bottom of the right front lamp unit housing. A headlamp leveling motor located on the back of each HID lamp unit is mechanically connected through an integral pushrod to the adjustable headlamp reflector. The automatic headlamp leveling system automatically adjusts the headlamp beam reflectors to compensate for changes in vehicle suspension height regardless of whether caused by the loading of the vehicle suspension or vehicle pitch changes caused by acceleration and deceleration. The actuator motors are automatically adjusted by the AHLM, which reads the front and the rear axle sensors to determine the suspension height changes. The circuitry of the AHLM provides a voltage signal to the electronic circuitry of both leveling actuator motors and the electronic circuitry of these stepper motors responds to the voltage inputs received from the AHLM to move the headlamp reflectors to the selected position. The headlamp leveling motors have a path to ground at all times. The automatic headlamp leveling components operate on battery current received only when the exterior lighting and the ignition switch are turned ON. PARK LAMPS The park lamps system includes the EMIC, the TIPM and the headlamp switch on the instrument panel. The front park lamp and side marker or position lamp bulbs each have a path to ground at all times through their connection to the FEM wire harness. The FEM wire harness has takeouts with eyelet terminals that are secured by ground screws to the front end sheet metal within the engine compartment. The rear park lamp, side marker lamp and license plate lamp bulbs have a path to ground at all times through a takeout and eyelet terminal of the body wire harness that is secured by a ground screw to the body sheet metal within the passenger compartment. The EMIC monitors a hard wired multiplex input from the headlamp switch, then sends the appropriate electronic headlamp switch status messages to the TIPM over the CAN data bus. The TIPM responds to these messages by providing a battery voltage output to the appropriate lamp bulbs through high side drivers on the front and rear, right and left park lamp feed circuits. For domestic market vehicles, the TIPM provides a battery saver (load shedding) feature for the park lamps, which will turn these lamps OFF if they are left ON for more than about eight minutes after the electronic ignition switch status messages from the WIN indicate the ignition LOCK position is selected. The EMIC provides a failsafe feature for the park lamps, which will send an electronic message to the TIPM to turn these lamps ON automatically if it detects no input from the headlamp switch. The TIPM also provides a fail-safe feature for the park lamps that will turn the headlamps and park lamps ON automatically whenever a loss of CAN bus communication is detected when the electronic ignition switch status messages from the WIN indicate the ignition ON position is selected. REAR FOG LAMPS Rear fog lamps are installed on vehicles manufactured for all export markets. The rear fog lamp system includes the headlamp switch, the EMIC and the TIPM. The rear fog lamps have a path to ground at all times through their connection to the rear fascia wire harness. The EMIC monitors a hard wired multiplex input from the headlamp switch to determine whether the rear fog lamps are selected, then sends electronic rear fog lamp switch status messages to the TIPM over the CAN data bus. The TIPM responds to this message by providing a voltage output to the rear fog lamps. The TIPM also sends the appropriate electronic messages to the EMIC to illuminate or extinguish the rear fog lamp indicator. The TIPM will automatically de-energize the rear fog lamps any time the front fog lamps are deselected or when the automatic headlamps feature turns the headlamps OFF. However, the rear fog lamps must always be turned ON manually, even after they've been turned OFF automatically. The TIPM also provides a battery saver (load shedding) feature for the rear fog lamps, which will turn these lamps OFF if they are left ON for more than about eight minutes after the electronic ignition switch status messages from the WIN indicate the ignition LOCK position is selected. SMARTBEAM® SYSTEM The optional SmartBeam® (auto high beam) system includes the SmartBeam® module with digital imager camera and electronic circuitry integral to the electrochromic inside rear view mirror, the SCM, the TIPM, the EMIC, the EVIC, the headlamp switch and the multi-function switch. First, the Auto High Beams option must be enabled using the customer programmable features function of the EVIC. Then the A (Automatic) position must be selected using the rotary knob of the headlamp switch, the headlamp beam selector switch must be in the high beam position and the appropriate ambient light conditions must be present. Finally, the vehicle speed must be greater than 32 kilometers-per-hour (20 miles-per-hour). Once all of these prerequisites have been met, the SmartBeam® camera and its circuitry within the electrochromic mirror automatically sends the appropriate electronic headlamp beam select switch status messages to the TIPM over the CAN data bus. The TIPM then responds to these messages by providing a pulse width modulated voltage output to the proper headlamp bulbs or the headlamp ballasts through the right and left low and high beam feed circuits to illuminate the headlamps. The TIPM also sends the appropriate electronic messages back to the EMIC to control the illumination of the high beam indicator. The SCM continues to monitor the multi-function switch, and will send the appropriate electronic messages to the EMIC, which relays these messages to the SmartBeam® circuitry in the inside rear view mirror and to the TIPM to manually invoke the beam select switch momentary optical horn (flash-to-pass) feature or, when a detent switch position is selected to override SmartBeam® operation. TRAILER TOW WIRING In addition to the trailer tow wiring provisions, domestic market vehicles equipped with an optional trailer tow package include right and left trailer tow stop/turn relays installed in the TIPM. When the TIPM receives the appropriate inputs for normal turn signal, hazard warning or brake lamp operation, it responds by also energizing or de-energizing these trailer tow relays. When a trailer tow relay is energized, it provides battery voltage from a fused B(+) fuse to the trailer lamps through the trailer tow wiring to synchronize the illumination and flash rate of the trailer brake and turn signal lamps with those of the tow vehicle. TURN SIGNAL LAMPS The turn signal lamps system includes the SCM, the EMIC, the TIPM and the multi-function switch on the steering column. The front turn signal lamp bulbs each have a path to ground at all times through their connection to the Front End Module (FEM) wire harness. The FEM wire harness has takeouts with eyelet terminals that are secured by ground screws to the body sheet metal within the engine compartment. The rear turn signal lamp bulbs have a path to ground at all times through a takeout and eyelet terminal of the body wire harness that is secured by a ground screw to the body sheet metal within the passenger compartment. On vehicles with the optional outside rear view mirror lamp modules, the lamp modules receive a path to ground from their respective driver or passenger door module. The SCM monitors a hard wired multiplex input from the multi-function switch to determine the status of the turn signal switch, then sends the appropriate electronic turn signal switch status messages to the TIPM over the CAN data bus. The TIPM responds to these messages by controlling a battery voltage output and the flash rate for either the right or left turn signal lamps. The TIPM also sends the appropriate electronic messages back to the EMIC to control the illumination and flash rate of the right or left turn signal indicators, as well as to control the click rate of an electromechanical relay soldered onto the EMIC electronic circuit board that emulates the sound emitted by a conventional turn signal flasher. On vehicles with the optional outside rear view mirror lamp modules, the TIPM also sends the appropriate electronic messages over the CAN bus to the driver and passenger door modules to control the illumination and flash rate of those lamps. The EMIC also provides a turn signal ON warning that will generate repetitive chimes to indicate that a turn signal has been active continuously for 1.6 kilometers (1 mile) with the vehicle speed greater than 22 kilometersper- hour (15 miles-per hour). Vehicles built for markets other than the United States and Canada have a revised distance threshold of 4 kilometers (2.49 miles) for this feature. The chime will continue until the turn signal input becomes inactive or until the vehicle speed message indicates that the speed is less than 22 kilometers-per-hour (15 miles-per-hour), whichever occurs first. |
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