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INTERIOR LIGHTING CONTROLThe EMIC contains an integral timer and logic circuit to perform both timer and control functions for the interior courtesy lamps. The EMIC uses hard wired inputs from the ignition switch, both door ajar switches on separate driver and passenger door ajar switch sense circuits, from the resistor multiplexed panel lamps dimmer circuitry of the left multi-function switch on the panel lamps dimmer signal circuit and its control logic to provide a battery current output to the courtesy lamps ON a courtesy lamp feed circuit. The EMIC control provides a theater-type fade-to-off feature that will slowly dim the courtesy lamps about five seconds after both doors are closed. The EMIC also provides an illuminated entry/exit feature by monitoring the door ajar and ignition switch inputs. When a door is opened with the ignition switch in the OFF position, the EMIC turns on the courtesy lamps. When the ignition switch is turned to the ON or Start positions, the EMIC turns the courtesy lamps OFF immediately with no theater dimming. When the ignition switch is turned from the ON position to the OFF position, the EMIC turns on the interior lights for about ten seconds or until the ignition switch is again turned to the ON or Start positions, whichever occurs first. The EMIC also provides a battery saver feature (load shedding) for the interior lighting. Unless the engine is running, the instrument cluster will automatically turn OFF the interior lights if they are left on for more than about twenty minutes, regardless of the status of the ignition switch, door ajar switch, or left multi-function switch inputs to the cluster.
The hard wired inputs and output of the EMIC interior lighting control can be diagnosed using conventional diagnostic methods; however, there are no other diagnostic tools available for the EMIC timer and logic circuitry. If the input and output components and circuits of the interior lighting system test OK, but the system fails to operate, the EMIC must be replaced.
LAMPS/LIGHTING - EXTERIOR
Turn Signal & Hazard Warning System
A turn signal and hazard warning system is standard factory-installed safety equipment on this model. The turn signal and hazard warning system includes the following major components, which are described in further detail elsewhere in this service information:
- Combination Flasher - The electronic combination flasher is located on the back of the left multifunction switch, beneath the upper steering column shroud on the top of the steering column.
- Front Side Marker Lamps - The front side marker lamps are located on the outboard ends of the two front fenders.
- Hazard Warning Switch - The hazard warning switch is integral to the left multi-function switch on the left side of the steering column. The hazard warning switch button protrudes from a dedicated opening in the shroud on the top of the steering column, just below the steering wheel.
- Turn Signal Cancel Cam - The turn signal cancel cam is integral to the clockspring, which is located beneath the shrouds on the top of the steering column, just below the steering wheel.
- Turn Signal Indicators - The two turn signal indicators, one right and one left, are integral to the Electro Mechanical Instrument Cluster (EMIC) located in the instrument panel.
- Turn Signal Lamps - The front turn signal lamps are integral to the front park/turn signal lamps located beside each headlamp on the front fender. The rear turn signal lamps are integral to the back-up/brake/rear turn signal/tail lamps located on either side of the rear of the quarter panels.
- Turn Signal Switch - The turn signal switch is integral to the left multi-function switch on the left side of the steering column. The left multi-function switch control stalk that actuates the turn signal switch protrudes from a dedicated opening in the shroud on the left side of the steering column, just below the steering wheel.
The turn signal system in this vehicle includes a turn signal-on warning chime feature. The EMIC electronic circuitry monitors the turn signal indicators as well as electronic vehicle speed and distance messages received from the Powertrain Control Module over the Programmable Communications Interface (PCI) data bus network to provide this feature. If an indicator remains illuminated continuously with the vehicle speed above about 25 km/h (15 mph) for a distance of greater than about 1.6 kilometers (1 mile), the EMIC generates a chime tone through an integral chime tone generator. For vehicles manufactured for markets other than the United States and Canada, the distance threshold for the turn signal-on chime warning is extended to about 4.0 kilometers.
Hard wired circuitry connects the turn signal and hazard warning system components 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 turn signal and hazard warning system components through the use of a combination of soldered splices, splice block connectors and many different types of wire harness terminal connectors and insulators. 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.
The turn signal system operates on battery current received on a fused ignition switch output (run) circuit so that the turn signals will only operate with the ignition switch in the ON position. The hazard warning system operates on non-switched battery current received on a fused B(+) circuit so that the hazard warning remains operational regardless of the ignition switch position. When the turn signal (left multi-function) switch control stalk is moved up (right turn) or down (left turn), the turn signal system is activated. When the turn signal system is activated, the circuitry of the turn signal switch and the combination flasher will cause the selected (right or left) turn signal indicator, front park/turn signal lamp, front side marker lamp and rear tail/stop/turn signal lamp to flash ON and OFF. With the hazard warning switch in the ON position, the hazard warning system is activated. When the hazard warning system is activated, the circuitry of the hazard warning switch and the combination flasher will cause both the right side and the left side turn signal indicators, front park/turn signal lamps, front side marker lamps and rear tail/stop/turn signal lamps to flash ON and OFF.
In order to provide the turn signal-on warning, the Electro Mechanical Instrument Cluster (EMIC) monitors vehicle speed and distance messages received from the Powertrain Control Module (PCM) over the Programmable Communications Interface (PCI) data bus and the hard wired turn signal switch input to the cluster electronic circuit board. If a turn signal remains indicated for a distance of greater than about 1.6 kilometers (1 mile) and the vehicle speed remains greater than about 24 km/h (15 mph), the EMIC generates a repetitive chime tone at a slow rate through its integral chime tone generator to provide an audible reminder that a turn signal has been left on. On vehicles manufactured for markets outside the United States and Canada, the distance threshold for the turn signal-on warning is extended to 4.0 kilometers. Once the warning chime begins to sound, it will continue until the turn signal is cancelled (either manually or mechanically), until the vehicle speed falls below about 24 km/h (15 mph), or until the ignition switch is turned to the OFF position, whichever occurs first. This feature is not activated by a hazard warning input to the instrument cluster.
During both the turn signal and the hazard warning operation, if the exterior lamps are turned OFF; the front park/turn signal lamps and the front side marker lamps will flash in unison. If the exterior lamps are turned On, the front park/turn signal lamps and the front side marker lamps will flash alternately. Refer to the owner's manual in the vehicle glove box for more information on the features, use and operation of the turn signal and hazard warning system.
WARNING: EYE PROTECTION SHOULD BE USED WHEN SERVICING GLASS COMPONENTS. PERSONAL INJURY CAN RESULT.
CAUTION:
- Do not touch the glass of halogen bulbs with fingers or other possibly oily surface, reduced bulb life will result.
- Do not use bulbs with higher candle power than indicated in the Bulb Application table. Damage to lamp and/or Daytime Running Lamp Module can result.
- Do not use fuses, circuit breakers, or relays having greater amperage values than indicated on the fuse panel or in the Owner's Manual.
NOTE: When it is necessary to remove components to service another, it should not be necessary to apply excessive force or bend a component to remove it. Before damaging a trim component, verify hidden fasteners or captured edges are not holding the component in place.
Lamp Systems
Each vehicle is equipped with various lamp assemblies. A good ground is necessary for proper lighting operation. Grounding is provided through a separate ground wire.
BRAKE LAMP SWITCH
The switch is mounted on the brake pedal mounting bracket under the instrument panel.
Vehicles equipped with the speed control option use a dual function brake lamp switch. The PCM monitors the state of the dual function brake lamp switch. Refer to the Brake for more information on brake lamp switch service and adjustment procedures.
The brake switch is equipped with three sets of contacts, one normally open and the other two normally closed (brakes disengaged). The PCM sends a 12 volt signal to one of the normally closed contacts in the brake switch, which is returned to the PCM as a brake switch state signal. With the contacts closed, the 12 volt signal is pulled to ground causing the signal to go low. The low voltage signal, monitored by the PCM, indicates that the brakes are not applied. When the brakes are applied, the contacts open, causing the PCM's output brake signal to go high, disengaging the speed control, cutting OFF PCM power to the speed control solenoids.
The second set of normally closed contacts supplies 12 volts from the PCM any time speed control is turned ON. Through the brake switch, current is routed to the speed control servo solenoids. The speed control solenoids (vacuum, vent and dump) are provided this current any time the speed control is ON and the brakes are disengaged.
When the driver applies the brakes, the contacts open and current is interrupted to the solenoids. The normally open contacts are fed battery voltage. When the brakes are applied, battery voltage is supplied to the brake lamps.
Fig.5 Combination Flasher:
COMBINATION FLASHER
The combination flasher is located in a dedicated connector receptacle integral to the back of the left multi-function switch housing on the top of the steering column, where it is concealed beneath the upper steering column shroud. The combination flasher is a smart relay that functions as both the turn signal system and the hazard warning system flasher, and is also sometimes referred to as the combo flasher. The combination flasher contains active electronic Integrated Circuitry (IC) elements. This flasher is designed to handle the current flow requirements of the factory-installed lighting. If supplemental lighting is added to the turn signal lamp circuits, such as when towing a trailer with lights, the combination flasher will automatically try to compensate to keep the flash rate the same.
The combination flasher is contained within a rectangular molded plastic housing that is black in color. The combination flasher has five blade-type terminals that connect it to the vehicle electrical system through five matching cavities in the left multi-function switch connector receptacle. While the combination flasher has an International Standards Organization (150)-type relay terminal configuration or footprint, the internal circuitry is much different. The combination flasher does not use standard ISO- relay inputs or provide ISO-relay type outputs or functions. The combination flasher should never be substituted for an ISO-relay or replaced with an ISO- relay; otherwise, component and vehicle damage may occur.
The combination flasher cannot be repaired or adjusted and, if faulty or damaged, it must be replaced.
The combination flasher has five blade-type terminals that are intended for the following inputs and outputs: ground, fused B(+), fused ignition switch output (run-acc), turn signal/hazard switch sense, and combination flasher output. Constant battery voltage is supplied to the flasher so that it can perform the hazard warning function, and ignition switched battery voltage is supplied for the turn signal function. The Integrated Circuit (IC) within the combination flasher contains the logic that controls the flasher operation and the flash rate. The IC receives sense ground inputs from the multi-function switch for the hazard flasher, right turn signal, and left turn signal. A special design feature of the combination flasher allows it to "sense" that a turn signal circuit or bulb is not operating, and provide the driver an indication of the condition by flashing the remaining bulbs in the affected circuit at a higher rate (120 flashes-per-minute or higher). Conventional flashers either continue flashing at their typical rate (heavy-duty type), or discontinue flashing the affected circuit entirely (standard-duty type).
Because of the active electronic elements within the combination flasher, it cannot be tested with conventional automotive electrical test equipment. If the combination flasher is believed to be faulty, test the turn signal and hazard warning system. Then replace the combination flasher with a known good unit to confirm system operation. (Refer to ELECTRICAL/LAMPS/LIGHTING - EXTERIOR DIAGNOSIS AND TESTING).
DAYTIME RUNNING LAMP MODULE
The Daytime Running Lights (Headlamps) System is installed on vehicles manufactured for sale in Canada only. A separate module, mounted on the cowl, controls the DRL.
The headlamps are illuminated when the engine is running and the parking brake is OFF. The lamps are illuminated at less than normal intensity.
FRONT PARK/TURN SIGNAL LAMP UNIT
The front turn signal/parking lamp is a separate module. Each module contains a housing, a lens, and bulb. The components are serviceable separately.
The parking light function is controlled by the headlamp switch located on the instrument panel. The turn signal function is controlled by the multi-function switch located on the steering column. Each front turn signal/parking lamp module can be serviced separately.
HEADLAMP UNIT
Headlamps on the Wrangler are sealed beam units. Each unit contains a high and low beam.
The headlamps are controlled by the headlamp switch and the multifunction switch. Each headlamp unit can be serviced individually.