Lighting and Horns: Description and Operation
LAMP SYSTEMSEach vehicle is equipped with various lamp assemblies. A good ground is necessary for proper lighting operation. Grounding is provided through a separate ground wire.
When changing lamp bulbs check the socket for corrosion. If corrosion is present, clean it with a wire brush and coat the inside of the socket lightly with Mopar Multi-Purpose Grease or equivalent.
HEAD LAMPS
Headlamps on the Cherokee are sealed beam units. Each module contains a low beam filament and a high beam filament.
The headlamps are controlled by the headlamp switch and the high beams by the multifunction switch. Each headlamp unit can be serviced individually.
HEADLAMP SWITCH
The headlamp switch is located on the instrument panel. The headlamp switch controls the parking lamps, the headlamps, the interior lamps, and instrument cluster illumination. The headlamp switch also contains a rheostat for controlling the illumination level of the instrument cluster lamps.
The headlamp switch has an off position, a parking lamp position, and a headlamp on position. High beams are controlled by the multifunction switch on the steering column. The headlamp switch cannot be repaired. It must be replaced.
SENTINEL HEADLAMP DELAY MODULE
The Headlamp Module delays the de-activation of the headlamps for 45+/-15 seconds after the ignition switch is turned OFF.
The driver engages the module by turning the ignition switch OFF, then turning the headlamps OFF. The module is mounted to a bracket attached to the inside of the instrument panel.
TAIL/TURN SIGNAL/STOP/BACK-UP LAMP
The rear tail lamp modules contains three bulbs, a lens, and a housing. One bulb is a two filament bulb used for tail light and stop lamp functions. One single filament bulb is for turn signal functions, The other bulb is a single filament bulb used for back-up light illumination.
Each tail lamp module can be serviced separately. Each bulb can also be serviced separately. The head- lamp switch controls tail lamp operation. The multi-function switch on the steering column controls turn signal operation, and the back-up light switch controls the back-up light operation. The brake lamp switch controls the stop lamp function.
FRONT TURN SIGNAL/PARKING LAMP
The front turn signal and parking lamp module contains a housing, a lens, and two bulbs.
The parking lamp function is controlled by the headlamp switch. The turn signal function is controlled by the multifunction switch on the steering column. Each bulb can be serviced separately.
CHMSL (CENTER HIGH MOUNTED STOP LAMP)
The center high mounted stop lamp (CHMSL) is mounted on the liftgate. The module consists of a housing, a lens, and a single filament bulb.
The CHMSL is controlled by the brake lamp switch.
DAYTIME RUNNING LAMPS
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 ignition switch is turned to the ON position. The DRL module receives a vehicle-moving signal from the vehicle speed sensor. This provides a constant head-lamps-on condition as long as the vehicle is moving. The lamps are illuminated at less than 50 percent of normal intensity.
SAFETY PRECAUTIONS
WARNING: EYE PROTECTION SHOULD BE USED WHEN SERVICING GLASS COMPONENTS. PERS0NAL 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 value than indicated on the fuse panel or in the Owners Manual.
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.
LAMPS (HARDWIRED)
The following lamps are hardwired to the cluster and are not part of the self-test:
Brake Warning (Red) - bulb test performed when the ignition switch is turned to the crank position
Full Time 4WD
Part Time 4WD High Beam
Left Turn Signal
Liftgate Ajar
The following lamps are bulb tested at ignition on by the appropriate system module.
ABS (Amber)
Check engine
SKIM
LAMPS (CCD)
The following lamps are controlled by the cluster via CCD messages. They are bulb tested (actuated) during the self-test procedure.
Airbag
Cruise Control
Low Fuel Warning
Low Washer Fluid
Upshift (If equipped)
Seat Belt
Sentry Key Immobilizer
Engine Temp (If equipped)
Battery (If equipped)
Low Oil Pressure Warning (If equipped)
The lowline cluster does not contain a check gauges telltale.
NOTE: THE SEAT BELT AND LOW WASHER FLUID SWITCHES ARE HARDWIRED TO THE CLUSTER. THE CLUSTER THEN DECIDES IF THE LAMP SHOULD ILLUMINATE BASED ON THE HARDWIRED INPUT.
HARDWIRED LAMPS
The cluster contains several hardwired lamps described earlier. These lamps are set up in two configurations: The lamp is supplied power by the cluster and the ground is supplied by the circuit being monitored, or the lamp is supplied with a ground in the cluster and power comes from a module or other device. Verification of the bulb filament may be required in all cases of an inoperative lamp. This will require removal of the cluster and bulb in question.
CCD CONTROLLED LAMPS
The cluster contains several CCD controlled lamps as described earlier. These lamps are part of the diagnostic self-test. When entering the self-test mode, operation of these lamps can be observed. If the bulb fails to operate during the self-test and the bulb filament is good, the cluster assembly will need to be replaced.