Part 2 of 2

HEADLAMP
Headlamps on the Ram Pick-Up are modular in design. The turn/park lamp module is incorporated into the headlamp module. The module contains two bulbs; a dual filament headlamp bulb, and a dual filament turn/park bulb. The Sport headlamp module has two separate bulbs for the headlamp illumination.

Headlamps and parking lamps are controlled by the headlamp switch. The multifunction switch mounted on the steering column controls the high beam function, and the turn signal function.

Fig.14 Power Distribution Center:

HEADLAMP RELAY
The headlamp (or security) relay is located in the Power Distribution Center (PDC) near the battery in the engine compartment. See the fuse and relay layout label affixed to the inside surface of the PDC cover for headlamp relay identification and location. The headlamp relay is a conventional International Standards Organization (ISO) micro relay. Relays conforming to the ISO specifications have common physical dimensions, current capacities, terminal patterns, and terminal functions. The relay is contained within a small, rectangular, molded plastic housing. The relay is connected to all of the required inputs and outputs through its PDC receptacle by five male spade-type terminals that extend from the bottom of the relay base. The ISO designation for each terminal is molded into the base adjacent to the terminal. The ISO terminal designations are as follows:
- 30 (Common Feed) - This terminal is connected to the movable contact point of the relay.
- 85 (Coil Ground) - This terminal is connected to the ground feed side of the relay control coil.
- 86 (Coil Battery) - This terminal is connected to the battery feed side of the relay control coil.
- 87 (Normally Open) - This terminal is connected to the normally open fixed contact point of the relay.
- 87A (Normally Closed) - This terminal is connected to the normally closed fixed contact point of the relay.

The headlamp relay cannot be adjusted or repaired. If the relay is damaged or faulty, it must be replaced.

The headlamp (or security) relay is an electromechanical switch that uses a low current input from the high-line or premium Central Timer Module (CTM) to control a high current output to the headlamps. The movable common feed contact point is held against the fixed normally closed contact point by spring pressure. When the relay coil is energized, an electromagnetic field is produced by the coil windings. This electromagnetic field draws the movable relay contact point away from the fixed normally closed contact point, and holds it against the fixed normally open contact point. When the relay coil is de-energized, spring pressure returns the movable contact point back against the fixed normally closed contact point. A resistor or diode is connected in parallel with the relay coil in the relay, and helps to dissipate voltage spikes and electromagnetic interference that can be generated as the electromagnetic field of the relay coil collapses.

The headlamp relay terminals are connected to the vehicle electrical system through a connector receptacle in the Power Distribution Center (PDC). The inputs and outputs of the headlamp relay include:
- The common feed terminal (30) is connected to ground at all times through a take out and eyelet terminal connector of the right headlamp and dash wire harness that is secured by a ground screw to the left fender inner shield near the PDC in the engine compartment.
- The coil ground terminal (85) is connected to the Central Timer Module (CTM) through the security relay control circuit. The CTM energizes the headlamp relay control coil by internally pulling this circuit to ground.
- The coil battery terminal (86) is connected to battery current at all times through a fused B(+) circuit that is internal to the PDC.
- The normally open terminal (87) is connected to the headlamps at all times through the beam select switch low beam output circuit. This circuit provides a path to ground for the headlamps through the common feed terminal when the headlamp relay control coil is energized by the CTM.
- The normally closed terminal (87A) is not connected to any circuit in this application, but is grounded through the common feed terminal when the headlamp relay control coil is de-energized.

The headlamp relay can be diagnosed using conventional diagnostic tools and methods.

HEADLAMP SWITCH
The headlamp switch module is located on the instrument panel. The headlamp switch controls the parking lamps, and the headlamps. A separate switch in the module controls the interior lamps and instrument cluster illumination. This switch also contains a rheostat for controlling the illumination level of the 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.

Multi-Function Switch:

MULTI-FUNCTION SWITCH
The multi-function switch is secured with two screws to the left side of the upper steering column housing at the top of the steering column, just below the steering wheel. The only visible parts of the multi-function switch are the control stalk that extends through a dedicated opening in the left side of the upper steering column shrouds, and the hazard warning switch push button that protrudes through an opening in the upper steering column shroud on the top of the steering column. The remainder of the switch, its mounting provisions, and its electrical connections are all concealed beneath the steering column shrouds. The multi-function switch control stalk has both nomenclature and International Control and Display Symbol graphics applied to it, which identify its many functions. An International Control and Display Symbol icon for "Hazard Warning" is applied to the top of the hazard warning switch push button.

The switch housing and its controls are constructed of molded black plastic. A single connector receptacle with up to twenty-four terminals is located on the back of the switch housing and connects the switch to the vehicle electrical system through a take out and connector of the instrument panel wire harness. The connector receptacle also has a threaded receptacle for a screw, which secures the wire harness connector to the switch connector receptacle.

The multi-function switch supports the following functions and features:
- Continuous Wipe Modes - The control knob of the multi-function switch provides two continuous wipe switch positions, low speed or high speed.
- Hazard Warning Control - The internal circuitry and hardware of the multi-function switch provide detent switching for activation and deactivation of the hazard warning system.
- Headlamp Beam Selection - The internal circuitry and hardware of the multi-function switch provide detent switching for selection of the headlamp high or low beams.
- Headlamp Optical Horn - The internal circuitry and hardware of the multi-function switch includes momentary switching of the headlamp high beam circuits to provide an optical horn feature (sometimes referred to as flash-to-pass), which allows the vehicle operator to momentarily flash the headlamp high beams as an optical signalling device.
- Intermittent Wipe Mode - The control knob of the multi-function switch provides an intermittent wipe mode with multiple delay interval positions.
- Turn Signal Control - The internal circuitry and hardware of the multi-function switch provide both momentary non-detent switching and detent switching with automatic cancellation for both the left and right turn signals.
- Washer Mode - A button on the end of the control stalk of the multi-function switch provides washer system operation when the button is depressed towards the steering column.

The multi-function switch cannot be adjusted or repaired. If any function of the switch is faulty, or if the switch is damaged, the entire switch unit must be replaced.

The multi-function switch uses conventionally switched outputs and a variable resistor to control the many functions and features it provides using hard wired circuitry. The switch is grounded at all times through a single wire take out with an eyelet terminal connector of the instrument panel wire harness that is secured by a nut to a ground stud located on the instrument panel armature, just above and to the left of the glove box opening. When the ignition switch is in the Accessory or ON positions, battery current from a fuse in the Junction Block (JB) is provided through a fused ignition switch output (RUN/ACC) circuit. Following are descriptions of the how the multi-function switch operates to control the many functions and features it provides:
- Continuous Wipe Modes - When the control knob of the multi-function switch is rotated to the High or Low positions, the circuitry within the switch provides a battery current output directly to the high or low speed brush of the wiper motor. When the control knob is in the OFF position, the circuitry within the switch connects the output of the wiper motor park switch to the low speed brush of the wiper motor.
- Hazard Warning Control - The hazard warning push button is pushed down to unlatch the switch and activate the hazard warning system, and pushed down again to latch the switch and turn the system OFF. When the hazard warning switch is latched (hazard warning OFF), the push button will be in a lowered position on the top of the steering column shroud; and, when the hazard warning switch is unlatched (hazard warning ON), the push button will be in a raised position. The multi-function switch hazard warning circuitry simultaneously provides a signal to the hazard warning sense of the combination flasher to activate or deactivate the flasher output, and directs the output of the flasher to the hazard warning lamps.
- Headlamp Beam Selection - The multi-function switch control stalk is pulled towards the steering wheel past a detent, then released to actuate the headlamp beam selection switch. Each time the control stalk is actuated in this manner, the opposite headlamp mode from what is currently selected will be activated. The internal circuitry of the headlamp beam selection switch directs the output of the headlamp switch through hard wired circuitry to activate the selected headlamp beam.
- Headlamp Optical Horn - The left multi-function switch control stalk is pulled towards the steering wheel to just before a detent, to momentarily activate the headlamp high beams. The high beams will remain illuminated until the control stalk is released. The internal circuitry of the headlamp beam selection switch provides a momentary ground path to the headlamp high beams.
- Intermittent Wipe Mode - When the multi-function switch control knob is rotated to the Delay position, the circuitry within the switch connects the output of the wiper motor relay to the low speed brush of the wiper motor and provides a battery current signal to the Central Timer Module (CTM). If the Delay mode is selected, the control knob can then be rotated to multiple minor detent positions, which actuates a variable resistor within the switch and provides a hard wired output to the CTM that signals the desired delay interval for the intermittent wiper feature.
- Turn Signal Control - The multi-function switch control stalk actuates the turn signal switch. When the control stalk is moved in the upward direction, the right turn signal circuitry is activated; and, when the control stalk is moved in the downward direction, the left turn signal circuitry is activated. The multi-function switch turn signal circuitry simultaneously provides a signal to the turn signal sense of the combination flasher to activate or deactivate the flasher output, and directs the output of the flasher to the proper turn signal lamps. The turn signal switch has a detent position in each direction that provides turn signals with automatic cancellation, and an intermediate, momentary position in each direction that provides turn signals only until the left multi-function switch control stalk is released. When the control stalk is moved to a turn signal switch detent position, the cancel actuator extends toward the center of the steering column. A turn signal cancel cam that is integral to the clockspring mechanism rotates with the steering wheel and the cam lobes contact the cancel actuator when it is extended from the multi-function switch. When the steering wheel is rotated during a turning maneuver, one of the two turn signal cancel cam lobes will contact the turn signal cancel actuator. The cancel actuator latches against the cancel cam rotation in the direction opposite that which is signaled. In other words, if the left turn signal detent is selected, the lobes of the cancel cam will ratchet past the cancel actuator when the steering wheel is rotated to the left, but will unlatch the cancel actuator as the steering wheel rotates to the right and returns to center, which will cancel the turn signal event and release the control stalk from the detent so it returns to the neutral OFF position.
- Washer Mode - Pushing the button on the end of the multi-function switch control knob towards the steering column provides a battery current output through the momentary single pole, single throw washer switch circuitry to operate the washer pump/ motor and provides a signal to the CTM. If the wipers are not operating when the washer switch is actuated, the CTM will operate the wiper motor for as long as the washer switch is depressed plus about three additional wipe cycles. If the wipers are operating in the intermittent mode when the washer switch is actuated, the CTM will operate the wiper motor at a fixed low speed for as long as the washer switch is depressed plus about three additional wipe cycles before the wipers return to the selected intermittent wipe interval.

TAIL LAMP
There are two types of tail lamp modules used on the Ram Truck. One type is integrated into the pick-up bed, The other is a bracket mounted module used on the Ram Truck Cab and Chassis. The Cab and Chassis module is made up of a housing, lens, and two bulbs. This type of module has license plate illumination built into the lens. The integrated pick up module contains a housing, lens, and two bulbs. A dual filament bulb is used for tail, stop, and turn signal operations. A separate bulb is used for back-up illumination.

Tail lamp functions are controlled by the headlamp switch. Turn signal operations are controlled by the multifunction switch. Stop lamp functions are controlled by the stoplamp switch. The back-up lamps are controlled by the back-up lamp switch on the transmission.

TURN SIGNAL CANCEL CAM
The turn signal cancel cam is concealed within the steering column below the steering wheel. The turn signal cancel cam consists of two lobes that are integral to the lower surface of the clockspring rotor. The clockspring mechanism provides turn signal cancellation as well as a constant electrical connection between the horn switch, driver airbag, speed control switches, and remote radio switches on the steering wheel and the instrument panel wire harness on the steering column. The housing of the clockspring is secured to the steering column and remains stationary. The rotor of the clockspring, including the turn signal cancel cam lobes rotate with the steering wheel.

The turn signal cancel cam is serviced as a unit with the clockspring and cannot be repaired. If faulty or damaged, the entire clockspring unit must be replaced. (Refer to RESTRAINTS/ CLOCKSPRING - REMOVAL).

The turn signal cancel cam has two lobes molded into the lower surface of the clockspring rotor. when the turn signals are activated by moving the multi-function switch control stalk to a detent position, a turn signal cancel actuator is extended from the inside surface of the multi-function switch housing toward the center of the steering column and the turn signal cancel cam. When the steering wheel is rotated during a turning maneuver, one of the two turn signal cancel cam lobes will contact the turn signal cancel actuator. The cancel actuator latches against the cancel cam rotation in the direction opposite that which is signaled. In other words, if the left turn signal detent is selected, the lobes of the cancel cam will ratchet past the cancel actuator when the steering wheel is rotated to the left, but will unlatch the cancel actuator as the steering wheel rotates to the right and returns to center, which will cancel the turn signal event and release the control stalk from the detent so it returns to the neutral OFF position.

DOOR AJAR SWITCH
The door ajar switches are mounted to the door hinge pillars. The switches close a path to ground for the Central Timer Module (CTM) when a door is opened, and open the ground path when a door is closed.

The door ajar switches cannot be repaired and, if faulty or damaged, they must be replaced.

READING LAMP
The overhead console in this vehicle is equipped with two individual reading and courtesy lamps. The lamp lenses are the only visible components of these lamps. The reading and courtesy lamp lenses are mounted in the overhead console housing between the garage door opener storage bin and the sunglasses storage bin. Each lamp has its own switch, bulb, reflector and lens; but both lamps share a common lamp housing within the overhead console.

The overhead console reading and courtesy lamps operate on battery current that is provided at all times, regardless of the ignition switch position. The ground feed for the lamps is switched through the integral reading and courtesy lamp switches or through the door jamb switches. Each lamp is designed and aimed to provide illumination that will be directed only to that side of the vehicle on which the lamp is located.

The reading and courtesy lamp lenses, bulbs and the lamp housing and reflector unit are available for service replacement. The reading and courtesy lamp switches, bulb holders and wiring are only available as part of the overhead console wire harness. If either of the lamp switches or bulb holders is faulty or damaged, the entire overhead console wire harness assembly must be replaced.

All reading and courtesy lamps located in the overhead console are activated by the doorjamb switches. When all of the doors are closed, these lamps can be individually activated by depressing the corresponding lens. When any door is open, depressing the lamp lenses to activate the lamp switches will not turn the lamps OFF.

See the owner's manual in the vehicle glove box for more information on the use and operation of the overhead console reading and courtesy lamps.