Lighting Systems: Other Chevrolet Silverado 2500

Module Information 1

Julian Date: The scan tool displays the date upon which the Body Control Module (BCM) was manufactured.

Manufacture Enable Counter (MEC): The scan tool displays the actual value for the MEC in the BCM. This information is for the assembly plant only.

Module Part Number: The scan tool displays the part number assigned to the BCM that is currently in the vehicle.

Software Design Suffix: The scan tool displays the version of the software part number in the BCM.

Software Part Number: The scan tool displays the software identification number (ID) in the BCM.

Module Information 2

Lighting Calibration Number: The scan tool displays the lighting configuration calibration part number in the BCM.

Lighting Suffix: The scan tool displays the lighting configuration identification number in the BCM.

Reminder Calibration Number: The scan tool displays the reminder warning calibration part number in the BCM.

Reminder Suffix: The scan tool displays the reminder warning identification number in the BCM.

RAP Calibration Number: The scan tool displays the RAP calibration part number in the BCM.

RAP Suffix: The scan tool displays the RAP identification number in the BCM.

Data

Ambient Light: The scan tool displays LIGHT when the ambient light sensor voltage is between 2.2-4.7 volts. The scan tool displays DARK when the ambient light sensor voltage is between 0.2-1.3 volts.

Ambient Light Sensor: The scan tool displays the output voltage of the ambient light sensor based on the intensity of light detected. As the light intensity increases, the sensor displayed voltage increases, In the LIGHT state, a high voltage (2.2-4.7 volts) is present and the DRL will be ON. In the DARK state, a low voltage (0.2-1.3 volts) is present and the headlamps will be ON.

Battery Voltage: The scan tool displays the battery system voltage.

Courtesy Lamp Timer: The scan tool displays the seconds left before the BCM turns the courtesy lamp relay OFF. The BCM uses this feature to control the components attached to the illuminated entry, the remote illuminated entry and the exit lighting circuits.

Dimming Potentiometer: The scan tool displays the voltage value indicating the position of the dome lamp switch (thumbwheel). The scan tool displays 0 (zero) volts when the headlamp switch is in the AUTO position and the daytime running lamps (DRL) are ON. The scan tool displays 10.5 volts when either the park lamps or the headlamps are turned ON and the dome lamp switch is in the FULL BRIGHT position.

High Beam Input: The scan tool displays the voltage in order to determine the state of the high beam headlamps. The scan tool displays 12.2 volts with the low beams ON and 0.8 volts with the high beams ON.

Inadvertent Power Timer: The scan tool displays the seconds left before the BCM turns the inadvertent power relay OFF. The BCM uses this feature to protect the battery against inadvertent battery rundown caused by components that are part of the courtesy lamp circuit. The inadvertent power relay is supplied power by the BCM for 2400 seconds (approximately 40 minutes), after the ignition is turned OFF.

RAP Timer: The scan tool displays the seconds left before the BCM turns the RAP relay OFF. The BCM uses this feature to allow the operation of the radio and the power windows for up to 1198 seconds (approximately 20 minutes), after the ignition is turned OFF. After the time has elapsed or the door is opened the BCM will open the ground circuit for the RAP relay.

Input 1

Cargo Lamp Switch: The scan tool displays the state of the switch. The scan tool displays ON when the cargo lights are requested by activation of the switch.

Drivers Door Jamb Sw.: The scan tool displays the position of the drivers door. The scan tool displays ACTIVE when the drivers door is open.

Horn Relay Input: The scan tool displays the state of the horn relay. The scan tool displays ACTIVE when the BCM senses that the horn relay is being commanded ON by the relay coil circuit being grounded.

Ignition 1: The scan tool displays the position of the ignition switch. The scan tool displays ACTIVE when the ignition switch is in the RUN or CRANK position.

Ignition 3: The scan tool displays the position of the ignition switch. The scan tool displays ACTIVE when the ignition switch is in the RUN position only.

Ignition Power Mode: The scan tool displays the position of the ignition switch. The scan tool displays OFF, RUN, CRANK and UNKNOWN. The UNKNOWN display is when the BCM can not determine the position of the ignition switch (between the OFF and RUN positions).

Last RFA Cmd. Since Wake-Up: The scan tool displays the last RFA commanded message from the BCM. The scan tool displays NONE when the BCM awakens from asleep status without receiving a RFA module request from a programmed key fob. The scan tool displays LOCK, UNLOCK or PANIC when the BCM is awake and a command is activated from the key fob to the RFA module.

Park Brake Switch: The scan tool displays the position of the park brake pedal. The scan tool displays SET when the park brake is depressed (switch closed). The BCM uses this data in controlling the operation of the park brake indicator, the reminder chime feature and the headlamp/DRL system.

Pass Door Unlock Input: The scan tool displays the state of the passenger door unlock relay. The scan tool displays ACTIVE when the BCM senses that the passenger door unlock relay is being energized.

RFA Message Since Wake-Up: The scan tool displays the last message sent to the BCM from the remote control door lock receiver.

RAP Relay Feedback: The scan tool displays the state of the RAP relay. The scan tool displays ON when the BCM activates the RAP relay.

Input 2

Cargo Lamp Switch: The scan tool displays the state of the switch. The scan tool displays ON when the cargo lights are requested by activation of the switch.

Courtesy Lamp Relay: The scan tool displays the state of the courtesy lamp relay. The scan tool displays ON when the BCM commands the courtesy lamps ON by providing a ground for the courtesy lamp relay.

Dim Pot Input: The scan tool displays the position of the dome lamp switch (thumb wheel) when the park lamps are ON. The scan tool displays ACTIVE when the dome lamp switch is in its normal position and the park lamps are ON.

Dome Lamp Switch: The scan tool displays the position of the dome lamp switch. The scan tool displays ON when the dome lamp switch is to its full up position past the detent.

Dome Override Switch: The scan tool displays the position of the dome override switch. The scan tool displays ON when the switch is activated and requesting the BCM to override the interior lighting.

Flash to Pass Switch: The scan tool displays the position of the flash to pass switch. The scan tool displays ON when the switch is pulled to activate the high beams momentarily while the switch is held.

Front Fog Lamp Switch: The scan tool displays the position of the front fog lamp switch. The scan tool displays ON when the front fog lamp switch is activated with the park lamps or headlamps ON.

Headlamp Relay Feedback: The scan tool displays the state of the headlamps. The scan tool displays ON when the headlamp and panel dimmer switch is manually turned to the ON position. The scan tool also displays ON when the switch is in the AUTO position and the ambient light sensor is in its DARK state.

High Beam Switch: The scan tool displays the position of the high beam switch. The scan tool displays ON when the high beam switch is activated.

Left Turn Signal: The scan tool displays the position of the turn signal switch. The scan tool displays ON when the left turn signal is activated. The BCM uses this data to activate the turn signal reminder chime after the vehicle has traveled 0.75 miles with the turn signal switch activated.

Park Lamps: The scan tool displays the state of the park lamps. The scan tool displays ON when the park lamps are activated by the BCM or the headlamp switch.

Right Turn Signal: The scan tool displays the position of the turn signal switch. The scan tool displays ON when the right turn signal is activated. The BCM uses this data to activate the turn signal reminder chime after the vehicle has traveled 0.75 miles with the turn signal switch activated.

Outputs

Chime: The scan tool displays the commanded state of the audible chime. The scan tool displays NONE when no audible chime is commanded. The scan tool displays HEAD LAMP, KEY IN IGNITION, SEAT BELT, TURN SIGNAL and PARK BRAKE as commanded.

Courtesy Lamp Relay: The scan tool displays the commanded state of the courtesy lamp relay. The scan tool displays ON when the BCM allows the courtesy lamp relay coil to go to ground to activate the courtesy lamps.

DRL Relay: The scan tool displays the commanded state of the DRL relay. The scan tool displays ON when the BCM allows the DRL relay coil to go to ground to activate the daytime running lamps.

Dimming: The scan tool displays the state of the panel dimmer switch. The scan tool displays ACTIVE when the park lamps are ON.

Front Fog Lamp Relay: The scan tool displays the commanded state of the front fog lamp relay. The scan tool displays ON when the BCM allows the front fog lamp relay to go to ground to activate the front fog lamps.

Headlamp Power Relay: The scan tool displays the commanded state of the headlamp power relay. The scan tool displays ON when the BCM allows the headlamp power relay to go to ground to activate the headlamps.

Horn Relay: The scan tool displays the commanded state of the horn relay. The scan tool displays ON when the BCM allows the horn relay to go to ground to activate the horn(s). The BCM will command this state when the PANIC button on the keyless entry transmitter is activated and when there is an unauthorized entry into the vehicle.

Inadvertent Power Relay: The scan tool displays the commanded state of the inadvertent power relay. The scan tool displays ON when the BCM allows the inadvertent power relay to go to ground. The BCM allows the component of the courtesy circuit to remain on until the BCM times it off.

Interior Lighting Mode: The scan tool displays the name of the feature which commanded the interior lights on. The scan tool displays NONE when the interior lights are not commanded on. The scan tool displays INTERIOR, ILLUM. ENTRY, EXIT LIGHTING and REMOTE ILLUM. when the respective mode commands the interior lights on.

Park Lamp Relay: The scan tool displays the commanded state of the park lamp relay. The scan tool displays ON when the BCM allows the park lamp relay to go to ground to activate the park lamps.

Passenger Door Unlock Relay: The scan tool displays the commanded state of the passenger door unlock relay. The scan tool displays ON when the BCM allows the passenger door unlock relay to go to ground to UNLOCK the passenger door(s). The BCM will command this state when the UNLOCK button on the keyless entry transmitter is activated twice within 3 seconds.

Rear Fog Lamp Relay: The scan tool displays the commanded state of the rear fog lamp relay. The scan tool displays ON when the BCM allows the rear fog lamp relay to go to ground to activate the rear fog lamps (Export Only).

RAP Relay: The scan tool displays the commanded state of the RAP relay. The scan tool displays ON when the BCM allows the RAP relay to go to ground. The BCM will allow operation of the radio and the power windows with the ignition OFF and the doors closed for up to 1198 seconds (approximately 20 minutes).

Scheme 179

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to TESTING FOR INTERMITTENT & POOR CONNECTIONS .

Headlamp Aiming

The screen method is preferred for aiming headlamps. If the headlamp is equipped with aiming pads, headlamp aiming may be performed using the alternate procedure.

Headlamp aiming is done with the vehicle's low beam lamps. The high beam lamps will be correctly aimed if the low beam lamps are aimed properly. If the high beam needs adjustment, follow the screen method using the high beam bulb as the reference for measurements.

Screen Method for Headlamp Aiming (Visual Aim)

Important: Some state and local laws specify requirements for headlamp aim. All of these laws must be complied with when performing any headlamp aiming operations.

Headlamp aim should be checked

1. When a new headlamp capsule is installed
2. If service or repairs to the front end area have (or may have) disturbed the headlamps or their mounting
3. The area will consist of a level surface large enough to allow for a vehicle and an additional 7.62 m (25 feet) measured from face of lamps to the front of the aiming screen.
4. The screen will be 1.52 m (5 ft) high x 3.66 m (12 ft) wide with a matte white surface well shaded from extraneous light, and properly adjusted to the floor on which the vehicle stands. Provisions may be made for moving the screen so it can be aligned parallel with the vehicle.
5. The screen shall be provided with a fixed vertical centerline, two laterally adjustable vertical tapes, and one vertically adjustable horizontal tape.
6. If a regular commercial aiming screen is not available, the screen may consist of a vertical wall having a clear uninterrupted area approximately 1.83 m (6 ft) high and 3.66 m (12 ft) wide. The surface should be finished with a washable non-gloss white paint.
7. After the aiming screen has been set up in its permanent location, it is necessary to paint a reference line on the floor directly under the lens of the lamps to indicate the proper location of the headlamps when they are being aimed: Distance between headlamps (1) Center line of screen (2) Adjustable vertical pointer (3) Adjustable horizontal tape (4) Diagram of light screen (5) Vertical center line ahead of right headlamp pointer position (6) 7.62 m (25 ft) (7) Car axis (8) Adjustable vertical pointer Horizontal center line of lamps Vertical center line ahead of left headlamp

Prior to aiming the headlamps, the following steps must be taken

Scheme 180

Scheme 181

1. Remove any snow, ice or mud from the vehicle.
2. The vehicle must have a full tank of gas.
3. Stop all other work on the vehicle.
4. If any service has been performed on the vehicle, make sure that all of the components are back in their original place.
5. The vehicle must be on a level surface.
6. The vehicle left tires must be aligned with the reference line extending from the screen with the headlamps aligned with the reference line.
7. Do not load any cargo in the vehicle.
8. The vehicle must contain one person or 72.56 kg (160 lb) on the driver's seat.
9. Inflate the tires to the proper pressure.
10. Simulate the vehicle loads if the intended use of the vehicle is for hauling heavy loads or towing a trailer.
11. Rock the vehicle in order to stabilize the suspension.
12. Turn on the headlamps to low beam and observe the left and the top edges of the high intensity zone on the screen. The edges of the high intensity zone should fall within the specifications.

Scheme 182

1. Open the hood.
2. Measure from the floor to the center of the headlamp bulb. (Some headlamps have an aim dot marked on the headlamp lens).
3. At the screen, measure from the floor and place the horizontal tape at the measured distance.
4. Measure from the reference line on the floor to the left headlamp bulb centerline.
5. At the screen, measure from the reference line and place the vertical tape at the measured distance.
6. Measure from the reference line on the floor to the right headlamp bulb centerline.
7. At the screen, measure from the reference line and place the vertical tape at the measured distance. Important: Do not cover the headlamp, this may cause excessive heat build up.
8. Turn on the low beam headlamps and block the light from projecting onto the screen from the passenger side headlamp.
9. Adjust the vertical aim of the headlamps to the specifications required by the state and the local authorities, or as shown in step number 8.
10. Rotate the headlamp adjuster (1) to change the vertical aim of the headlamp.
11. Repeat the aiming procedure for the passenger side headlamp while blocking the light from projecting onto the screen from the driver side headlamp.
12. Close the hood.
13. This illustration represents the Visual Optics Left (VOL) pattern.
14. This illustration represents the Visual Optics Right (VOR) pattern.
15. This illustration represents all headlamps, except the VOL and VOR.
16. This illustration represents the high beam pattern for all headlamps, including VOL and VOR.

Tool Required

J 25300-203 Composite Headlight Aimer Adapter Instructions for use accompany the tool.

This procedure may only be used on headlamps equipped with aiming pads. Adjustment settings are embossed on the headlamp lens. They are typically located near the aiming pads. In some cases, the adjustment settings are located in other areas of the lens. They will be represented by a number followed by the letter V or the letter H.

1. Remove any snow, ice or mud from the vehicle.
2. The vehicle should be fully assembled and all other work stopped while the headlamp aiming is being done.
3. The vehicle should contain cargo or be loaded to represent normal vehicle use.
4. Tires should be properly inflated.
5. Rock the vehicle to stabilize the suspension.
6. Using J 25300-203 , adjust the headlamps to the specifications required by state and local authorities.

Scheme 183

1. Disconnect the electrical connector from the fog lamp.
2. Remove the push pin retainers that attach the fog lamp to the bracket.
3. Remove the fog lamp adjuster bolt and spring from the adjuster nut.
4. Remove the fog lamp from the fog lamp bracket.
5. Remove the fog lamp bracket bolts and bracket, as needed.

Fog Lamp Aiming Procedure

The front fog lamps must be aimed for proper illumination of the road. The front fog lamp aim should be checked when a new front fog lamp assembly is installed, or if service or repairs in the front end area may have disturbed the front fog lamp mounting.

Preparation Procedure

Important: Horizontal aim is not adjustable on this vehicle. Vertical aim is adjusted by an adjusting nut located on the rear of the fog lamp. Prior to aiming the headlamps, perform the following steps

1. Completely assemble all of the components on the vehicle.
2. Park the vehicle on a level surface.
3. Stop all unnecessary operations or work on the vehicle that affect the vehicle trim.
4. Close the doors and ensure that the vehicle has no load other than the driver.
5. Stabilize the suspension by rocking the vehicle sideways.
6. Ensure that the fuel level is 1/2 full.
7. Ensure that the tires are inflated to the proper pressure.
8. Ensure that the driver or a similar weight, approximately 75 kg (165 lb), is in the vehicle driver seat.

Scheme 184

1. Park the vehicle on a level surface 7.6 m (25 ft) away from a wall or other flat surface.
2. Measure the distance from the floor to the center of the fog lamp (5).
3. Using this measurement, mark the horizontal centerline of the fog lamp (1) on the flat surface directly in front of the vehicle.
4. Turn ON the fog lamps.
5. Reach under the rear lower edge of the front fascia in order to access the fog lamp vertical adjustment screw on the rear of the fog lamp.
6. Adjust the fog lamp so that the top edge of the fog lamp beam pattern is 100 mm (4 in) below the horizontal centerline.
7. Turn OFF the fog lamps.

Exterior Lamps

The exterior lighting system consist of the following lamps

1. The Headlamps
2. The Daytime Running Lamps (DRL)
3. The Fog Lamps
4. The Park, Tail and Marker Lamps
5. The Turn Signal Lamps
6. The Stoplamps
7. The Backup Lamps
8. The Exterior Courtesy Lamps
9. The Clearance Lamps
10. The Cargo Lamp
11. The Underhood Lamp

Headlamps

The headlamps may be turned on in two different ways. First, when the driver places the headlamp switch in the HEADLAMP position, for normal operation. Second, with the headlamp switch placed in the AUTO position, for automatic lamp control (ALC). During ALC control the headlamps will be in day time running lamp (DRL) operation in daylight conditions, or low beam operation in low light conditions.

The automatic lamp control (ALC) system and the DRL feature can be temporarily disabled by performing the following procedure

Note. The ALC and DRL cannot be turned off on the Canadian vehicles.

1. Turn the ignition to RUN.
2. Press the DOME OVERRIDE button four times within six seconds.

A chime will sound informing you that the system is off. The system will remain disabled until the ignition is cycled off and then on or by pressing the DOME OVERRIDE button four more times within six seconds. The chime will sound again signaling that the system has been reactivated.

The engine wiring harness junction block supplies battery positive voltage to the normally open headlamp relay switch circuit. The TBC 10 A fuse in the engine wiring harness junction block supplies battery positive voltage to the headlight and dimmer switch assembly. The body control module (BCM) also supplies battery positive voltage to the headlamp relay coil circuit for automatic headlight control. The coil circuit of the headlamp relay is then grounded at G102. When the driver places the headlamp switch in the HEADLAMP position, the headlamp relay is energized. Depending on the position of the dimmer switch, the current flow is to both the left and right headlamp fuse, and to either the low or high beam headlamps. From the dimmer switch, the current flow is to ground at G203. The TCB 10 A fuse in the engine wiring harness junction block supplies battery positive voltage to the headlight and dimmer switch assembly flash to pass switch. When the headlamp dimmer switch handle is pulled toward the driver, both flash-to-pass switches close, one grounding the high beam circuit at G203. A second flash to pass switch also closes providing battery positive voltage to the BCM flash-to-pass input. With the headlights in the low beam position, the high beams may be momentarily turned on or flashed with the dimmer switch handle.

If the headlight switch is left in the ON position, the inadvertent power control feature will turn off the headlights approximately 10 minutes after the ignition switch is turned to the OFF position. If the driver places the headlight switch in the ON position after the ignition switch has been turned OFF, or if the ignition switch is in the CCY position, the headlights will remain on until turned off or the battery runs dead.

The high beam indicator is illuminated when the instrument cluster receives a class 2 serial data message from the BCM that the high beams are illuminated.

Daytime Running Lamps (DRL)

The ambient light sensor is a light sensitive transistor that varies its voltage signal to the body control module (BCM) in response to changes to the outside (ambient) light level. When the BCM receives this signal it will either turn on the daytime running lamps (DRL) or the headlight relay for auto headlamp operation. Any function or condition that turns on the headlights will cancel the daytime running lamps operation. The daytime running lamps (DRL) separate lamps independent of the headlamps. With the headlight switch in the OFF position, the DRL will either be turned ON or OFF, after an approximate 8 second delay depending on whether daylight or low light conditions are sensed. The DRL 10 A fuse in the engine wiring harness junction block supplies battery positive voltage to the daytime running lamp (DRL) relay switch contacts. The IGNE 10A fuse in the engine wiring harness junction block supplies ignition positive voltage to the DRL relay coil. When the BCM energizes the DRL relay in daylight conditions, the current flow is to both DRL lamps and to ground G100. The DFL will operate when the ignition switch is in the FUN position, the gear selector is not in the PARK position and the parking brake is released. When these conditions have been met and the ambient light sensor indicates daytime conditions, the DRL will illuminate.

The automatic lamp control (ALC) system and the DRL feature can be temporarily disabled by performing the following procedure

Note. The ALC and DRL cannot be turned off on the Canadian vehicles.

1. Turn the ignition to RUN.
2. Press the DOME OVERRIDE button four times within six seconds.

A chime will sound informing you that the system is off. The system will remain disabled until the ignition is cycled off and then onto by pressing the DOME OVERRIDE button four more times within six seconds. The chime will sound again signaling that the system has been reactivated.

Fog Lamps

With both the ignition switch in the [RUN] position, and the park lamps ON, the fog lights will illuminate when the driver places the fog lamp switch in the ON position. The FOG LPS 15 A fuse in the engine wiring harness junction block supplies battery positive voltage to the fog lamp relay switch circuit. The park lamp relay supplies battery positive voltage to the fog lamp relay coil. With the headlamp switch in either the park or headlamp position, and the fog lamp switch is paced in the ON position, the body control module (BCM) will energize the fog lamp relay control circuit. The BCM receive: the park lamp ON signal from the interior park lamps supply voltage signal circuit. The current flow is from the fog lamp relay to both front fog lamps and to ground G100. The state of the fog lamps will remain the same until the fog lamp switch position is changed, or the ignition switch is cycled OFF and ON. Fog lamp operation will be cancelled whenever the park lamps, are turned OFF or the high beam headlights have been selected.

The rear fog lamps are controlled in much the same way, however the front fog lamps must be on in order to turn on the rear fog lamps. The rear fog lamps have there own relay, and both the relay control and current flow are the same as the front fog lamps.

Park, Tail and Marker Lamps

The park, tail and marker lamps, including the license lamps, are turned on when the headlamp switch is placed in the PARK or ON position or anytime the headlights are requested. The PARK LPS 30A fuse in the engine wiring harness junction block supplies battery positive voltage to both the park lamp relay switch contacts and the park lamp coil circuit. The body control module BCM) provides a ground or control circuit to the park lamp relay coil circuit. When the park lamps are turned on the BCM energizes the park lamp relay. Current flow is from the park lamp relay to the FR PRK 10 A fuse, RR PRK 10A fuse, LR PRK 10 A fuse, and the TRL PRK 15A fuse, and to their respective park and marker lamps. The front park and marker lamps are grounded at G100. The rear park and marker lamps are grounded at G401. The license lamps are grounded at G401. If the headlight switch is left in the ON position, the inadvertent power control feature will turn off the park, tail and marker lamps approximately 10 minutes after the ignition switch is turned to the OFF position. If the driver places the headlight switch in the ON position after the ignition switch has been turned OFF, or if the ignition switch is in the ACCY position, the park, all and marker lamps will remain on until turned off or the battery runs dead.

The CTSY LMP 15A fuse in the engine wiring harness junction block supplies battery positive voltage to both the inadvertent power relay switch contacts and the inadvertent power relay coil circuit. The body control module (BCM) provides a ground or control circuit to the park lamp relay coil circuit.

When the driver presses the cargo lamp switch, the BCM energizes the inadvertent power relay. Current flow is from the inadvertent power relay to the cargo lamps. The cargo lamps are grounded at G203.

Exterior Courtesy Lamps

The SEO 1 15A fuse in the engine wiring harness junction block supplies battery positive voltage to both the exterior courtesy lamp relay switch contacts and the exterior courtesy lamp relay coil circuit. When the driver or passenger door is opened the body control module (BCM) energizes the exterior courtesy lamp relay. Current flow is from the exterior courtesy lamp relay to both outside rear view mirror exterior courtesy lamps. The exterior courtesy lamps are grounded at G200 and G203. When the remote function actuation (RFA) module receives a door unlock command from the remote function actuator transmitter, the RFA module will send a message to the body control module (BCM) indicating that an UNLOCK command has been received. The BCM must have inputs that indicate that the ignition switch is OFF, all the doors are closed. The BCM will activate the exterior courtesy lamp relay illuminating the power outside mirror exterior courtesy lamps. If the door locks are activated to the LOCK position, or if the ignition switch is turned to either the ON or RUN position the exterior courtesy lamps will deactivate immediately.

When an outside door handle is lifted or a door is opened, the exterior courtesy lamps illuminate.

Turn Signal Lamps

The HAZ LP 20A fuse in the engine wiring harness junction block supplies battery positive voltage to the hazard switch assembly. The TURN 20A fuse in the engine wiring harness junction block supplies ignition positive voltage to the turn signal switch assembly. With the ignition switch in the RUN or START position, ignition positive voltage is connected through the turn signal and hazard switch assembly to the flasher module which is grounded at G203. When the turn signal switch is placed in either the left or right position, the circuit is complete from the flasher module through the turn signal switch to the turn signal lamps and to ground. The flasher module then sends an on-off voltage signal through the turn signal switch to either the left or right turn signals and their instrument panel cluster (IPC) indicator. The audio chime is also activated when the turn signals are on. When the hazard switch is pressed, all turn signal lamps will flash including both IPC turn indicators. The front turn signals are grounded at G100. The rear turn signals are grounded at G401.

For trailer wiring, separate turn signal circuits are connected through the turn signal switch for the trailer wiring harness. The TRL L TRN 10A fuse and TRL R TRN 10A fuse in the engine wiring harness junction block supplies the signal for the trailer turn signal lamps.

Stop Lamps

The STOP LPS 20A fuse in the engine wiring harness junction block supplies battery positive voltage to the normally open stop lamp switch. When the driver presses the brake pedal, the switch contacts close and battery positive voltage is supplied to both the VEH STOP 10A fuse and the CHMSL 10A fuse. Battery positive voltage is also supplied by the STOP LPS 20A fuse in the engine wiring harness junction block to the turn signal switch. The current flow is now to the stop lamps which are grounded at G401. The center high mounted stop lamp (CHMSL) is grounded at G410 or G203 for pick ups.

For trailer wiring, a separate stop lamp circuit is connected through the engine wiring harness junction block from the CHMSL 20A fuse to the trailer wiring harness.

Backup Lamps

The B/U LP 25A fuse in the engine wiring harness junction block supplies battery positive voltage to the normally open backup lamp switch. When driver places the gear selector lever is in the REVERSE position, the backup lamp switch closes and the current flow is from the backup lamp switch through the VEH B/U 15A fuse to the backup lamps. The backup lamps are grounded at G401.

For trailer wiring, a separate backup lamp circuit is connected through the engine wiring harness junction block from the TRLR B/U 10A fuse to the trailer wiring harness.

Clearance Lamps

The clearance lamps are turned on when the headlamp switch is placed in the PARK or ON position or anytime the headlights are requested. The PARK LPS 30A fuse in the engine wiring harness junction block supplies battery positive voltage to both the park lamp relay switch contacts and the park lamp coil circuit. The body control module (BCM) provides a ground or control circuit to the park lamp relay coil circuit. When the park lamps are turned on the BCM energizes the park lamp relay. Current flow is from the park lamp relay to the INT PRK 10A fuse, and to clearance lamps. The clearance lamps are grounded at G200.

Cargo Lamp & Underhood Lamp

The inadvertent power relay provides battery positive voltage to the cargo lamp and the underhood lamp. When the respective normally open switch is closed, the switch provides a ground circuit and the lamp illuminates. The cargo lamp is grounded at G203. The underhood lamp is grounded at G102.

Headlamp Leveling (Export)

The IGN 1 10A fuse in the engine wiring harness junction block supplies battery positive voltage to the to both the headlamp leveling switch and the headlamp leveling motors through different terminals in the junction block. The headlamp leveling switch varies the amount of current to the actuators causing them to move simultaneously up or down to each selected position. Ground for the actuators and the switch are supplied by G100.

Interior Lamps

The interior lighting consist of the following two groups. This first group includes lamps that may not be dimmed.

1. Cargo lamp
2. Courtesy/Illuminated entry lamps
3. Dome lamps
4. Door courtesy lamps
5. I/P compartment lamp
6. Map lamps
7. Reading lamps
8. Vanity mirror lamp

Courtesy/Illuminated Entry Lamps

The courtesy/illuminated lamps, may be manually turned on or off by placing the interior lamp switch in the ON or OFF position. When the driver places the dome lamp defeat witch in the OFF position, the courtesy/illuminated entry lamps will be disabled. If an outside door handle is lifted or a door is opened, the courtesy/illuminated entry lamps illuminate. After all the doors have been closed the courtesy/illuminated entry lamps will remain illuminated approximately 15 seconds. The courtesy/illuminated entry lamps will also turn on prior to and door being opened, and remain illuminated approximately 40 seconds when the driver removes the ignition key.

The courtesy/illuminated entry lamps, include two different groups of lamps. The first group includes these courtesy/illuminated entry lamps which are not individually controlled

1. Dome lamps
2. Door courtesy lamps
3. I/P courtesy lamps

These lamps illuminate when a door jamb switch, courtesy lamp switch of a remote keyless entry (RKE) command is received by the body control module (BCM).

The CTSY LP 15A fuse in the engine wiring harness junction block, supplies battery positive voltage to the inadvertent power relay coil and switch circuits. The BCM provides a ground to control the inadvertent power relay. The normally open inadvertent power relay switch closes and provides power these courtesy lamps. When a courtesy lamp request input is received by the BCM, the BCM will energize the courtesy lamp relay. The normally open courtesy lamp relay switch closes, illuminating the lamps by grounding the courtesy lamp ground circuit to G203.

The BCM will immediately turn off the courtesy lamps if a door lock command is received with all the doors closed, or if the ignition switch is turned to either the ON or RUN position.

The second group includes these individually controlled lamps, each will a separate switch

1. I/P compartment lamp
2. Map lamps
3. Reading lamps
4. Underhood lamp
5. Vanity mirror lamps

The CTSY LP 15A fuse in the engine wiring harness junction block, supplies battery positive voltage to the inadvertent power relay coil and switch circuits. The BCM provides ground to energize the inadvertent power relay, which provides voltage to these lamps. Ground is provided to the IP compartment lamp at G200. Ground is provided to the underhood lamp at G102. Ground is provided to all others at G203.

Keyless Entry Interior illumination

When the driver uses the door key in order to unlock the doors, the body control module (BCM) receives a door unlock signal. The BCM must have inputs that indicate that the ignition switch is OFF, the courtesy lamp switch is OFF and all the doors are closed. The BCM will then activate the interior lamps. The courtesy lamps will remain on, approximately 15 seconds after the door is closed. The BCM will then turn them off through the theater dimming feature. If the door locks are activated to the LOCK position, or if the ignition switch is turned to either the RUN or CRANK position the courtesy lamps will turn off immediately.

When the driver uses the remote function actuator transmitter to unlock the doors, trunk or presses the panic button, the BCM will keep the courtesy lamps on approximately 40 seconds. When the driver uses the remote function actuator transmitter to lock the doors, the BCM will keep the courtesy lamps on approximately 2 seconds. If the ignition switch is turned to either the RUN or CRANK position the courtesy lamps will turn off immediately. The BCM will also keep the courtesy lamps on approximately 40 seconds, after an alarm event is completed.

Vanity Lamps

The inadvertent power relay provides battery positive voltage to each vanity mirror lamp. When the vanity mirror cover on the sunshade is opened, its switch closes to provide a ground circuit and the vanity lamp illuminates. The vanity lamps are grounded at G203.

IP Compartment Lamp

The inadvertent power relay provides battery positive voltage to the instrument panel compartment lamp. When the IP compartment is opened, its switch closes to provide a ground circuit and the IP compartment lamp illuminates. The IP compartment lamp is grounded at G102.

Cargo Lamp

The inadvertent power relay provides battery positive voltage to the cargo lamp. When the cargo lamp switch is closed, ground is provided and the cargo lamp illuminates.

Battery Rundown Protection/Inadvertent Power

In the event that any of the interior lamps supplied voltage by the inadvertent power relay and ground from the courtesy lamp relay were to remain on when the ignition is OFF after a period of 20 minutes, the BCM will deactivate the inadvertent power relay turning OFF all of the lamps on that circuit to prevent total battery discharge. Only when the ignition switch is cycled back to the RUN position will the BCM reset the internal timer and reactivate the inadvertent power relay. When the inadvertent power relay is not energized, the BCM utilizes the inadvertent power courtesy lamp supply voltage circuit to monitor for a courtesy lamp switch request signal. If a courtesy lamp switch is activated, the BCM will receive the signal to energize the inadvertent power relay by grounding the control circuit.

Interior Lamps Dimming

The second group includes lamps which may be dimmed. This group may use a combination of vacuum fluorescent (VF) illumination and of incandescent lamps.

1. Door switches and window switches
2. HVAC control head assembly
3. Radio
4. The instrument panel cluster (IPC)
5. Other interior controls and switches

When the ignition switch is turned to the ON position, the radio's vacuum fluorescent (VF) displays turn on at maximum brightness. When the park lamps are on, all incandescent back lighting turn on at the dimming level indicated by the IP dimmer switch.

At the same time all vacuum fluorescent (VF) displays dim to match the indicated dimming level. Battery positive voltage is supplied through the PARK LPS 30A fuse in the engine wiring harness junction block, to the normally open park lamp relay switch contacts. The panel dimmer switch potentiometer receives both its voltage and ground from the headlamp switch and is an input to the BCM. When the driver selects a dimming setting by moving, the IP dimming switch potentiometer, all incandescent back lighting lamps are provided with a specific voltage. The incandescent back lighting lamps are then grounded at G203 and G200. When the IP dimmer switch is moved from MIN to MAX, all vacuum fluorescent (VF) displays, as well as all incandescent back lighting respond from Minimum intensity to maximum brightness in response to the IP dimmer switch.

The driver may select parade mode by manually turning on the park lamps during daylight conditions. The front park lamp circuit supplies voltage to the instrument panel cluster, radio and HVAC assembly for a park lamp on input, and the displays will become full bright.

Scheme 185