Lamps/Lighting - Interior - 2012 Jeep Wrangler JK Factory Service Manual

WARNING

WARNING:

To avoid serious or fatal injury, eye protection should be used when servicing any glass components.

CAUTION:

Do not use bulbs with higher candle power than indicated in the Bulb Application table . In addition, do not use fuses, circuit breakers or relays having greater amperage value than indicated on the fuse panel or in the Owner's Manual. Damage to lamps, lenses, wiring and other related electrical components can result.

DESCRIPTION

The interior lighting system for this vehicle includes incandescent lighting on two separate circuits: the dome/courtesy lamp circuit and the panel lamps dimmer circuit. The lamps on the dome/courtesy circuit include:

Cargo Lamp (3) - A switchable cargo/second row dome lamp is standard equipment only on vehicles with four doors to illuminate both the cargo and second row seat areas. This lamp is located in the lower center surface of the sport bar rear crossmember and is controlled by the courtesy lamp circuit.
Courtesy Lamp (1) - An optional single courtesy lamp is located on the lower edge of the instrument panel to illuminate the driver side foot well area. On vehicles so equipped, this lamp is controlled by the courtesy lamp circuit.
Dome Lamp (2) - A standard equipment dome lamp is located in the lower center surface of the speaker enclosure/sound bar to illuminate the interior of the vehicle. This lamp is controlled by the courtesy lamp circuit. On some models the standard rear dome lamp is replaced with a rear dome/reading lamp that includes a switch that is actuated by depressing the lamp lens.

Most controls on the instrument panel and elsewhere in the interior of the vehicle are illuminated by the panel lamps dimmer circuit for night visibility. All except the automatic transmission gear selector bezel lamp have miniature incandescent bulbs, Light-Emitting Diode (LED) units or a combination of the two lighting types that are soldered to internal circuit boards and are not serviceable.

The optional automatic transmission gear selector bezel lamp is located on the left side of the gear selector lever mechanism just beneath the bezel on the floor panel transmission tunnel. This lamp has a replaceable incandescent bulb.

Other components of the interior lighting system for this vehicle include:

Door Ajar Switches - A door ajar switch is integral to the door latch mechanism of each front and rear door.
Instrument Cluster - The ElectroMechanical Instrument Cluster (EMIC) is also known as the Cab Compartment Node (CCN) in this vehicle. The EMIC/CCN is located in the instrument panel above the steering column opening, directly in front of the driver. (Refer to 08 - Electrical/8J - Instrument Cluster - Description) .
Left Multi-Function Switch - The left (lighting) multi-function switch is located on the steering column, just below the steering wheel. A control sleeve on the control stalk that extends from the left side of the switch is used to select the panel lamps dimmer lighting level or the courtesy lamp circuit operating mode. (Refer to 08 - Electrical/8L - Lamps and Lighting/Lamps/Lighting - Exterior/SWITCH, Multifunction - Description) .
Swing Gate Ajar Switch - A swing gate ajar switch is integral to the latch mechanism of the swing gate.
Steering Control Module - The Steering Control Module (SCM) is located within the left multi-function switch housing on the top of the steering column, just below the steering wheel. (Refer to 08 - Electrical/8E - Electronic Control Modules/MODULE, Steering Column - Description) .
Totally Integrated Power Module - The Totally Integrated Power Module (TIPM) is located in the engine compartment near the battery. (Refer to 08 - Electrical/8W - Wiring/Power Distribution - Description) .

Hard wired circuitry connects the interior 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 interior 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. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness connectors, splices and grounds.

OPERATION

The lamps of the interior lighting system can be divided into two general classifications based upon the circuit that controls their operation: The courtesy lamp circuit, or the panel lamps dimmer circuit. Following are paragraphs that briefly describe the operation of each of these interior lighting circuits.

The lamps and the hard wired circuits between components related to the interior 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 interior lighting system or the electronic controls or communication between modules and other devices that provide some features of the interior lighting system. The most reliable, efficient, and accurate means to diagnose the interior lighting system or the electronic controls and communication related to interior lighting system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

COURTESY LAMP CIRCUIT

The courtesy lamp circuit includes the dome lamp located on the speaker enclosure/sound bar near the center, the cargo/second row dome lamp located on the rear sport bar crossmember near the center of vehicles with four doors, and on vehicles so equipped a courtesy lamp located on the driver side lower edge of the instrument panel. The lamps in the courtesy lamp circuit are provided with battery voltage and ground by the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) using internal drivers through a courtesy lamp driver circuit and two ground circuits based upon electronic ajar switch status message inputs received from the Totally Integrated Power Module (TIPM) over the Controller Area Network (CAN) data bus. The EMIC also uses electronic left multi-function switch and ignition switch status message inputs received from the Steering Control Module (SCM) over the Local Interface Network (LIN) data bus to control these outputs.

After all of the ajar switch inputs to the TIPM transition to open, the EMIC will keep the courtesy lamps illuminated for about 30 seconds, then fade the lamps to OFF (theater dimming) over about 3 seconds. The EMIC also provides courtesy lamp operation based upon the electronic left multi-function switch status messages received from the SCM, and provides an illuminated entry feature in response to certain electronic message inputs received from the Sentry Key REmote Entry Module (SKREEM) (also known as the Wireless Control Module/WCM) and the Occupant Restraint Controller (ORC) over the CAN data bus. A courtesy lamp DEFEAT mode based upon an electronic left multi-function switch status message received from the SCM will cause the EMIC to override normal courtesy lamp operation based upon any ajar switch inputs to the TIPM.

For those lamps in the courtesy lamp circuit with independent switching, such as the cargo/second row dome lamp, the EMIC provides a second battery feed to this switch using another internal driver through a separate courtesy lamp load shed circuit. The EMIC provides a battery saver (load shedding) feature for all courtesy lamps, which will automatically turn these lamps OFF if they are left ON for more than about eight minutes with the ignition switch in the OFF position.

PANEL LAMPS DIMMER CIRCUIT

The panel lamps dimmer circuit actually includes several circuits. These circuits control the illumination and dimming level of the heater-air conditioner controls and the automatic transmission gear selector bezel lamp. All lamps in the panel lamps dimmer circuits are provided a path to ground at all times through a hard wired ground circuit. These lamps are illuminated by a 12-volt Pulse Width Modulated (PWM) output of the EMIC through the panel lamps dimmer circuit.

This shared PWM output synchronizes the selected illumination intensity level of all of the lamps in the panel lamps dimmer circuits. The EMIC uses electronic left multi-function switch status and dimming level message inputs received from the SCM over the LIN data bus. The SCM sends the proper left multi-function switch status and dimming level messages based upon the exterior lighting selection of the control knob and the dimming level selection of the control sleeve on the left multi-function switch control stalk.

The EMIC, the instrument panel switch pod and the radio use the dimming level messages from the SCM to control the illumination intensity of their own back lighting and controls. In addition, when the control sleeve of the left multi-function switch is moved to the PARADE (or funeral) mode detent position, all of the Vacuum Fluorescent Display (VFD) units in the vehicle are illuminated at their full intensity levels for increased visibility when the vehicle is driven during daylight hours with the exterior lights turned ON. The PARADE mode has no effect on the illumination intensity of incandescent panel lamps.

DIAGNOSIS AND TESTING - LAMPS/LIGHTING - INTERIOR

WARNING:

To avoid serious or fatal injury on vehicles equipped with airbags, disable the Supplemental Restraint System (SRS) before attempting any steering wheel, steering column, airbag, seat belt tensioner, impact sensor or instrument panel component diagnosis or service. Disconnect and isolate the battery negative (ground) cable, then wait two minutes for the system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the SRS. Failure to take the proper precautions could result in accidental airbag deployment.

NOTE:
When diagnosing the interior lighting circuits, remember that high generator output can burn out bulbs rapidly and repeatedly; and, that dim or flickering bulbs can be caused by low generator output or poor battery condition. If one of these symptoms is a problem on the vehicle, be certain to diagnose the battery and charging system, then repair as necessary.

NOTE:
A good ground is necessary for proper lighting operation. If a lighting problem is being diagnosed that involves multiple symptoms, systems, or components, the problem can often be traced to a loose, corroded, or open ground.

The lamps and the hard wired circuits between components related to the interior 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 interior lighting system or the electronic controls or communication between modules and other devices that provide some features of the interior lighting system. The most reliable, efficient, and accurate means to diagnose the interior lighting system or the electronic controls and communication related to interior lighting system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

COURTESY LAMP CIRCUIT

CONDITION	POSSIBLE CAUSES	CORRECTION
A SINGLE LAMP IN THE COURTESY LAMP CIRCUIT DOES NOT ILLUMINATE	1. Ineffective or missing bulb.	1. Test and replace the courtesy lamp bulb if required.
	2. Ineffective lamp switch.	2. Test and replace a map/reading lamp switch if required.
	3. Ineffective ground circuit.	3. Test and repair the open ground circuit if required.
	4. Ineffective feed circuit.	4. Test and repair the open feed circuit if required.
ALL LAMPS IN THE COURTESY LAMP CIRCUIT DO NOT ILLUMINATE	1. Ineffective ground circuit.	1. Test and repair the open ground circuit if required.
	2. Ineffective feed circuit.	2. Test and repair the open feed circuit if required.
	3. Courtesy DEFEAT feature turned ON.	3. Turn courtesy DEFEAT feature OFF.
	4. Ineffective courtesy lamp control circuit.	4. Test and repair the courtesy lamp control circuit if required.
	5. Ineffective EMIC inputs or outputs.	5. Use a diagnostic scan tool to test the EMIC inputs and outputs. Refer to the appropriate diagnostic information.
A SINGLE LAMP IN THE COURTESY LAMP CIRCUIT DOES NOT EXTINGUISH	1. Ineffective lamp switch.	1. Test and replace a map/reading lamp switch if required.
ALL LAMPS IN THE COURTESY LAMP CIRCUIT DO NOT EXTINGUISH	1. Ineffective ajar switch.	1. Test and replace a door ajar or liftgate ajar switch if required.
	2. Ineffective ajar switch sense circuit.	2. Test and repair the shorted ajar switch sense circuit if required.
	3. Ineffective TIPM inputs or outputs.	3. Use a diagnostic scan tool to test the TIPM inputs and outputs. Refer to the appropriate diagnostic information.
	4. Ineffective EMIC inputs or outputs.	4. Use a diagnostic scan tool to test the EMIC inputs and outputs. Refer to the appropriate diagnostic information.

PANEL LAMPS DIMMER CIRCUIT

NOTE:
As part of the exterior lighting failsafe feature, upon ignition ON, all of the panel lamps dimmer circuit lamps will illuminate at full intensity and the exterior park lamps and headlamp low beams will illuminate regardless of the left multi-function switch control knob position if the Steering Control Module (SCM) cannot detect an input from the left multi-function switch, or if there is a loss of data bus communication.

CONDITION	POSSIBLE CAUSES	CORRECTION
A SINGLE LAMP DOES NOT ILLUMINATE	1. Ineffective or missing bulb or Light Emitting Diode (LED) unit.	1. Test and replace the lamp bulb or LED unit if required.
	2. Ineffective ground circuit.	2. Test and repair the open lamp ground circuit if required.
	3. Ineffective feed circuit.	3. Test and repair the open lamp feed circuit if required.
A SINGLE LAMP DOES NOT EXTINGUISH	1. Ineffective feed circuit.	1. Test and repair the shorted lamp feed circuit if required.
ALL LAMPS DO NOT ILLUMINATE	1. Ineffective ground circuit.	1. Test and repair the open lamp ground circuit if required.
	2. Ineffective feed circuit.	2. Test and repair the open lamp feed circuit if required.
	3. Ineffective EMIC inputs or outputs.	3. Use a diagnostic scan tool to test the EMIC inputs and outputs. Refer to the appropriate diagnostic information.
ALL LAMPS ILLUMINATE AT FULL INTENSITY AT IGNITION ON	1. Ineffective EMIC inputs or outputs.	1. Use a diagnostic scan tool to test the EMIC inputs and outputs. Refer to the appropriate diagnostic information.
ALL LAMPS ILLUMINATE AT FULL INTENSITY AT IGNITION ON	2. Loss of data bus communication.	2. Use a diagnostic scan tool to test the data bus. Refer to the appropriate diagnostic information.

SPECIFICATIONS

COURTESY LAMPS

BULB APPLICATION TABLE

LAMP	BULB
COURTESY	906
CARGO	578
FRONT DOME	578

PANEL LAMPS

BULB APPLICATION TABLE

LAMP	BULB
GEAR SELECTOR BEZEL	37