Murano by Bruce Wayne

White Paper 2006 LED Rear Combination Lamp Assembly for 2003-2005 Nissan Murano Revision 0 25 February 2006

Author Patrick Shine jetshine@gmail.com

DISCLAIMER: The information in this white paper is provided without warranty or guarantee of suitability to a particular purpose. The author assumes no liability for use of this information. No part of this document may be reproduced without written permission of the author. The information presented in this document is considered intellectual property provided without charge and may not be used for commercial purposes.

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2006 LED Rear Combination Lamp Assembly White Paper Revision 0

Table of Contents White Paper 2006 LED Rear Combination Lamp Assembly for 2003-2005 Nissan Murano........ 1 Revision 0 25 February 2006...................................................................................................... 1 1. 2003-2005 Murano Rear Combination Lamp Design ............................................................ 3 1.1 Theory of Operation........................................................................................................ 4 2. 2006+ Murano Rear Combination Lamp Design ................................................................... 4 2.1 Theory of Operation........................................................................................................ 6 3. Implementation: LED Interface Module................................................................................. 6 3.1 Input Logic State............................................................................................................. 7 3.2 Power Switching Stage ................................................................................................... 8 3.3 Interface Module Circuit................................................................................................. 9 3.4 Interface Module Construction ..................................................................................... 11 3.5 Interface Module Installation........................................................................................ 18 4. Glossary ................................................................................................................................ 21 5. References............................................................................................................................. 21 Table of Figures Figure 1. 2003-2005 Rear Combination Lamp ............................................................................... 3 Figure 2. 2005 RCLA Pin Assignments ......................................................................................... 3 Figure 3. 2006 RCLA Features...................................................................................................... 5 Figure 4. 2006 RCLA Pin Assignments ........................................................................................ 5 Figure 5. 2006 RCLA Internal Schematic ...................................................................................... 6 Figure 6. Infiniti FX35 Service Manual - Diagram for Rear Combination Lamp Control Unit.... 7 Figure 7. Interface Circuit Schematic .......................................................................................... 10 Figure 8. Location of LED Interface Unit ................................................................................... 12 Figure 9. Interface Board Layout................................................................................................. 13 Figure 10. Hair-pinning technique............................................................................................... 15 Figure 11. Interface Board, Top Side............................................................................................ 15 Figure 12. Interface Board, Bottom Side ...................................................................................... 16 Figure 13. Wire Feed-Thru Location ............................................................................................ 16 Figure 14. Interface Board Installed in Project Box .................................................................... 17 Figure 15. Application of RTV to Enclosure Cover .................................................................... 17 Figure 16. Completed Installation - STOP Mode ........................................................................ 20 Table of Tables Table 1. Connector P1 Pin Assignments......................................................................................... 3 Table 2. MY 2006 RCLA Connector P1 Pin Assignments ............................................................ 5 Table 3. LED Array Truth Table ................................................................................................... 7 Table 4. Implementation Options for LED Interface..................................................................... 8 Table 5. Detailed Parts List........................................................................................................... 14

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1. 2003-2005 Murano Rear Combination Lamp Design On Model Year (MY) 2003-2005, the Rear Combination Lamp Assembly (RCLA) is comprised of 3 bulbs and 4 filaments. A diagram and pin description is shown below.

Figure 1. 2003-2005 Rear Combination Lamp

2005 COMBINATION LAMP WIRING SCHEMATIC COMBINATION LAMP

P1 SIDE MARKER STOP TURN GROUND

GRN/YLW

GRN/WHT

GRN

BLK

<Value>

Figure 2. 2005 RCLA Pin Assignments

Table 1. Connector P1 Pin Assignments

Function

P1-1 P1-2 P1-3 P1-4

Side Marker Lamp Stop Lamp Turn Signal Lamp Ground (Common)

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Signal Type (On/Off) +12VDC / 0 VDC +12VDC / Open +12VDC / 0 VDC 0VDC / 0VDC

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1.1 Theory of Operation The top lamp is a 5W marker lamp, which is activated by the Body Control Module (BCM) when the headlight system is activated. When headlights are active, +12V is distributed from the BCM to this bulb via pin P1-1. When inactive, 0VDC is distributed to this pin. A ground path is provided via pin P1-4 (shared with other lamps in assembly). The middle lamp is a 21W turn signal lamp, which is controlled by the BCM when the driver has commanded a turn via the turn signal stalk. This light can also be activated during certain remote control operations (door lock/unlock), or when the hazard warning flasher circuit is energized. When active, +12V is distributed from the BCM to this bulb via pin P1-3. When inactive, 0VDC is distributed to this pin. A ground path is provided via pin P1-4 (shared with other lamps in assembly). The bottom lamp is a dual-filament bulb used as both a marker lamp and a stop lamp. The marker lamp filament dissipates 5W when active, while the stop lamp dissipates 21W when active. The marker filament is active when the headlight system is activated via the lighting multi-function control stalk. When headlights are active, +12V is distributed from the BCM to this filament via pin P1-1. The STOP filament is active when the driver depresses the brake pedal. When active, +12VDC is distributed from the Stop Lamp Switch (Module E116) to this filament via pin P1-2. When inactive, an open circuit is presented to this pin. A ground path for both filaments in this bulb is provided via pin P1-4 (shared with other lamps in assembly). 2. 2006+ Murano Rear Combination Lamp Design Starting with MY 2006 Muranos, the RCLA was re-designed as a multi-function LED array. The 2006 RCLA (right-hand and left-hand) is a form-fit replacement for the part it replaces on previous model years. Benefits of LED-based lighting include lower power consumption, increased Mean Time Between Failures (MTBF), and smaller foot-print, allowing for use in tighter locations. LED lighting is becoming increasingly prevalent in contemporary car designs. The 2006 Rear Combination Lamp Assembly (RCLA) is comprised of an LED array (consisting of 24 light-emitting diodes wired in parallel) and a single side-marker LED. A photo, diagram and pin description is shown below:

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Connector P1 Side Marker LED Blackberry 7130e

LED Array

(for size comparison)

Reflective Strip

Figure 3. 2006 RCLA Features 2006 COMBINATION LAMP WIRING SCHEMATIC COMBINATION LAMP_1

P1 LED ARRAY SIDE MARKER CATH_DIM CATH_BRIGHT

GRN/YLW

GRN/WHT

GRN

BLK

<Value>

Figure 4. 2006 RCLA Pin Assignments Table 2. MY 2006 RCLA Connector P1 Pin Assignments

Function

P1-1 P1-2 P1-3

LED Array Anode Side Marker LED Anode LED Array Low Brightness Cathode / Side Marker Cathode LED Array High Brightness Cathode / Side Marker Cathode

P1-4

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Signal Type (On/Off) +12VDC / 0 VDC +12VDC / 0 VDC Ground / Open Ground / Open

2006 LED Rear Combination Lamp Assembly White Paper Revision 0

AN_STOP_TURN

CATH_DIM 3K

LED

STOP/TURN ARRAY D5

AN_MARKER

CATH_BRT LED

SIDE MARKER

Figure 5. 2006 RCLA Internal Schematic

2.1 Theory of Operation The LED array is used for multiple purposes on the RCLA. The following functions (which were accomplished via discrete filaments/lamps on the 03-05 RCLA) are absorbed by the LED array: à Stop (high brightness) à Turn (high brightness) à Marker (low brightness) The LED array can be active in one of two states. For HIGH brightness, +12VDC is applied to pin P1-1, and Ground is applied to pin P1-4. For LOW brightness, +12VDC is applied to pin P11, and Ground is applied to pin P1-3. Pins P1-3 and P1-4 cannot be permanently tied to ground together. Internally, the circuit path exiting pin P1-3 includes a resistive element (to dim the array). If both pins are tied to ground, the current will bypass the resistive path and go directly through pin P1-4, since that is the easier path to ground. Therefore, it is necessary to use a current switch to toggle the path to ground. More details are discussed in the Implementation section of this white paper. The LED array draws approximately 0.65A when active. The Side Marker LED is activated when the headlight system is active. To illuminate this LED, +12VDC is applied to pin P1-2, and ground can be applied to either P1-3 or P1-4 (either path will cause the LED to illuminate at the same brightness). This LED draws 0.12A when active. 3. Implementation: LED Interface Module Since the signals from the 2003-2005 Murano will not directly interface with the signal requirements of the 2006 RCLA, an interface module is required to adapt the signals. Specifics about the 2006 MY Murano were not available at the time this white paper was written, however it is reasonable to assume that there is an additional module near the LH & RH RCLA to interface the signals from the BCM and Stop Lamp Switch to the RCLA. This assumption is corroborated by the fact that the Infiniti FX model (also manufactured by Nissan) uses a similar LED array, and according to its service manual, has a separate module (“Rear Combination Lamp Control Unit”) to control the LED arrays (see red-circled call-out in Figure 6 below).

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Figure 6. Infiniti FX35 Service Manual - Diagram for Rear Combination Lamp Control Unit

The author chose to implement a design similar to the Infiniti FX, using a control module to interface the signals from the BCM to those required by the LED RCLA. However, instead of using a single interface module located somewhere near the aft end of the vehicle, a smaller interface module is used near each RCLA, for a total of 2 modules. The interface device can be thought of as two stages. An input logic stage is required since there are more inputs from the 2003-2005 Murano than there are outputs on the 2006 LED array. The second stage is the power switching stage, which controls power to the LED array. 3.1 Input Logic State To design the input logic stage, a truth table is defined, as shown in Table 3. Table 3. LED Array Truth Table

Lights Stop Turn 0 0 0 0 1 1 1 1

0 0 1 1 0 0 1 1

0 1 0 1 0 1 0 1

An_ An_ Array Mrkr 0 0 1 0 1 0 0 0 1 1 1 1 1 1 1 1

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Cath_Brt Cath_Dim (Pin 4) (Pin 3) 0 1 1 1 1 1 0 1 0 1 1 1 1 1 0 1

Array 0 Brt Brt 0 Dim Brt Brt Dim

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Note that, for the case where both the turn signal is ON and the Brake signal is ON, the LED high-brightness cathode is switched OFF. This is required because there is no way to distinguish between the turn signal being OFF, and temporarily in the OFF state while it is flashing. The implementation of this behavior is via an XOR (Exclusive-OR) gate. There are several ways to implement this truth table. A summary of options, along with advantages and disadvantages, is shown in Table 4: Table 4. Implementation Options for LED Interface Implementation Option Advantages

7400-Series Logic Gates - Fast switching

Disadvantages

- Requires external power supply - Requires drivers - Higher part count - Higher cost

Discrete Components - Fast Switching - Inexpensive - Size - No external power supply required - Small losses due to voltage drops across diodes

Relays - Easier to implement - No external power supply required - Higher Cost - Slow switching times - Prone to mechanical failure - Size

In order to meet the goal of a module that resides near the RCLA, the author chose to implement a discrete component solution (option 2). The other options, while possible, would be size- and cost-prohibitive. A solution using relays or 7400-series logic Integrated Circuits (ICs) would have to be relocated somewhere inside the cabin. Logic gates are realized using diodes and transistors. For further reading, a discussion of logic gates implemented in this fashion can be found on this website, http://www.hanssummers.com/electronics/misc/gates/index.htm or in many reference texts (see References section). 3.2 Power Switching Stage Since the essence of controlling this LED array is by switching the cathodeâ&#x20AC;&#x2122;s path to ground, and because it draws a relatively large amount of current (approx. 0.65A) when active in the BRIGHT state, a Metal-Oxide Semiconductor Field-Effect Transistor (MOSFET) device is the ideal solution for controlling the high-brightness path. A MOSFET is a voltage controlled current switch that is capable of working with high power devices (10-50W) with low loss and extremely fast switching speeds (on the order of 15 ns, or 15/1,000,000,000th of a second). The low-brightness state of the LED array dissipates much less power (about 150 mW), therefore a simpler Bi-polar Junction Transistor (BJT) may be used. BJTs offer similar switching speeds, but are not suited for high current applications. A common BJT can dissipate up to about 500 mA, which is sufficient to control the low-brightness path. The side marker LED adds a negligible overhead to either path when active.

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The input logic state provides the control to the switching of the MOSFET and BJT. Since there is no external power supply, the input logic stage also provides the forward power for lighting the LED array and side marker. 3.3 Interface Module Circuit The interface circuit schematic is shown on next page as Figure 7.

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Figure 7. Interface Circuit Schematic

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Circuit Description The two main inputs for the input logic circuit are TURN and STOP, connectors 3 and 2 respectively in Figure 7. Resistors R1, R2 are pull-down resistors to prevent indeterminate states when a signal is not applied to inputs TURN and STOP. R1 is a 10Ω, 10W wire-round resistor, while R2 is a 1kΩ resistor. A 10Ω resistor is required for R1 so that the circuit draws more current when TURN is selected. The BCM flasher circuit includes a feature to detect a burnt bulb (which causes an apparent low current draw). Because the LED array draws less current (0.65A) than the filament bulb (21W – 1.75A) it expects, the flasher circuit believes there is a dead bulb, and causes the flasher to toggle at a higher rate as an indication to the driver. The 10Ω resistor addresses this problem. Diodes D1-D2 act as buffers to prevent voltage bleeding into one input when the other is active. Together, they also form an “OR” gate. If either is active, the applied voltage flows through R3, and then through either of D3 or D4 to ground. R3 is sized so that if this condition is true, BJT Q1 will remain in the OFF state. While in the OFF state, almost no current passes through the Collector-Emitter path of the BJT, therefore the voltage at the node formed by the intersection of R4 and R5 is above VTH, the threshold to activate MOSFET Q2. A voltage in the range +(10.6, 12.6)VDC is supplied to the LED array anode (connector 6) through diode D6, while the cathode (connector 9) returns through the drain pin on Q2. If both inputs TURN, STOP are active, then the XOR condition is desired. +12V is supplied through R3 and D5 to supply a bias current to the base of Q1. When this occurs, Q1 operates in the forward-active regime. As a result, a larger current flows through R4, through the C-E junction of the BJT down to ground. The voltage at the junction of R4, R5 drops below VTH for transistor Q2, which then causes the LED array to turn off. When +12VDC is applied to the SIDE MARKER input (connector 1), +12V is supplied directly to the output pin ANODE_MARKER (connector 7), and also to the LED Array anode (connector 6). The voltage applied to the SIDE MARKER input also turns on transistor Q3, which allows current from the LED array low-brightness cathode to flow through to ground. As a result, both the side marker LED and the LED array light up when the headlight system is turned on. The LED array will be in the low-brightness state for this condition. If all three inputs are active (TURN, STOP, SIDE MARKER), the LED array will alternate between BRIGHT and DIM to indicate turn signal flashes, while the side marker LED remains on steady. 3.4 Interface Module Construction The module sits between the RCLA and the vehicle wiring. The recommended location for the interface unit is near the RCLA. The interface unit should be inserted in the wire harness between the RCLA and its P1 connector. Refer to Figure 8.

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VEHICLE CONNECTOR

COMBINATION LAMP

LED INTERFACE UNIT

Figure 8. Location of LED Interface Unit

Build the interface module in the following order: 1. Circuit Board Layout The author constructed this board on an experimenter’s board, available from Radio Shack. See the detail parts list for part numbers. To construct the board, lay out the components according to Figure 9. Layout tips: • It is helpful to first layout the smaller, flat components (such as resistors and diodes), solder those components on the reverse side, then place the larger components and solder. • Because a commercial off-the-shelf (COTS) circuit board is used, several jumpers are needed to make the proper connections. For shorter runs, use the trimmed legs from diodes/resistors. Bend into shape using needle-nose pliers. For longer runs, an insulated wire is suggested. Use 24AWG solid conductor wire. • Some components are “hair-pinned” to fit properly. To make a hair pin bend, use a needle-nose pliers to bend one leg 180°. Use a cutter to trim the legs to equal lengths (see Figure 10) • Be sure to use proper solder technique. Use a soldering iron with a properly-tinned tip. Clean the tip of the solder often using a wet sponge. Use rosin-core solder.

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AS VIEWED FROM TOP SIDE

LED BRT CATH

R5 J7 Q1

J4 J2

J8 SIDE MARKER INPUT

D1*

LED DIM CATH

LED ARY ANODE

STOP INPUT

D6* D2*

GROUND INPUT TURN INPUT

SIDE MARKER ANODE

D4 D3

NOTE 1: DIODES (D) MUST BE INSTALLED IN PROPER ORIENTATION. MATCH LINE ON CASE WITH LINE ON THIS DRAWING! NOTE 2: TRANSISTORS (Q) MUST BE INSTALLED AS SHOWN. FOR Q2, THE TAB SIDE IS INDICATED BY THE THICKER LINE ON THE DRAWING NOTE 3: JUMPERS (J) USE COMMON SOLID WIRE. CAN USE TRIMMED-OFF LEADS FROM DIODES. LONGER LENGTHS (E.G. J7) SHOULD USE INSULATED WIRE. *Shown Hair-pinned. Cathode end is UP.

Figure 9. Interface Board Layout

A complete parts list is shown on the next sheet. Figure 11 & Figure 12 depict the completed circuit board.

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DIODE, 1N4148, SWITCHING GENERAL PURPOSE IC BOARD PROJECT ENCLOSURE 3"X2"X1" WIRE, 22AWG, SOLID RUBBER-BONDED WASHERS

2 2 2 1 8

2 2 2 12

RS RS RS RS

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276-1620 276-159 270-1801 278-1221

271-1118 271-132 271-1132 276-1653

271-1335

276-1617

VENDOR P/N 276-2072

2.59 2.29 2.29 5.99 0.13

0.99 1.79 0.99 2.59

0.99

2.59

1 1 2 1 8

1 1 1 1

2.59 2.29 4.58 5.99 1.04

0.99 1.79 0.99 2.59

5 PER PACKAGE WIRE-WOUND TYPE SUBS FOR 270K 25 IN PACKAGE

1.98 5 PER PACKAGE

2.59

P/N NET COST QTY COST COMMENTS 1.99 2 3.98

50 PER PACKAGE 2 PER PACKAGE USE PLASTIC COVER CONTAINS 3 SPOOLS PROCURE LOCALLY - HARDWARE STORE RTV SEALANT 1 4.99 1 4.99 PROCURE LOCALLY - AUTOMOTIVE STORE WATER-TIGHT CONNECTOR, 4-POS, 2 2.99 2 5.98 PROCURE LOCALLY - AUTOMOTIVE MALE STORE WATER-TIGHT CONNECTOR, 4-POS, 2 2.99 2 5.98 PROCURE LOCALLY - AUTOMOTIVE FEMALE STORE GROMMET, ROUND, 1/4" 2 0.50 2 1.00 PROCURE LOCALLY - AUTOMOTIVE STORE DOUBLE-SIDE MOUNTING TAPE 3M 1 2.99 1 2.99 ROLL ********************************************* END OF REPORT ******************************************** ************************ TOTALS 53 39.68 52.34 NOTES RS = RADIO SHACK

R2 R1 R3 D1 D2 D3 D4 D6 D7

4 RS

Q1 Q3 R4 R5 R6 6 RS

QTY VENDOR 2 RS

ID Q2

RESISTOR, 1K, 1/4W, 5% RESISTOR, 10 OHM, 10W, 5% RESISTOR, 220K, 1/4W, 5% DIODES, RECTIFIER, ASSORTED

RESISTOR, 10K, 1/4W, 5%

PART DESCRIPTION TRANSISTOR, N-CHANNEL, MOSFET, IRF-510 TRANSISTOR, BJT, NPN

Table 5. Detailed Parts List

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Step 1

Step 2

Step 3

Figure 10. Hair-pinning technique

Figure 11. Interface Board, Top Side

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Step 4

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Figure 12. Interface Board, Bottom Side

2. Construct Enclosure for Interface Board The circuit board must be enclosed in a weather-proof enclosure, since the module will be installed on the vehicle outside the main cabin. The enclosure must seal out water and debris, and withstand temperatures in the normal commercial temperature range (0°70°C). If the board is enclosed in the Radio Shack 270-1801 project box, additional steps must be take to ensure a weather-tight seal. Use a electric drill and ¼” drill bit to create a hole in one end – this will be used to feed wires out. See Figure 13 for suggested placement. Use a rubber grommet of an appropriate size to fill the hole.

Drill here

Figure 13. Wire Feed-Thru Location

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Place the circuit board and wires inside the enclosure. Feed the wires through the rubber grommet. When properly placed, the assembly should reflect Figure 14 (shown below).

Figure 14. Interface Board Installed in Project Box

After the board is placed inside the enclosure assembly, the box can be closed out with the cover. Before securing the cover, apply a small bead of RTV silicone sealant around the periphery of the cover lip â&#x20AC;&#x201C; this will cure into a rubber weather seal. Remove excess RTV using a knife. It is suggested to test the module on the vehicle before this close-out procedure.

RTV

Figure 15. Application of RTV to Enclosure Cover

Before using the included screws to secure the cover to the enclosure, install a rubberbonded washer on each screw for a complete seal.

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3.5 Interface Module Installation Follow the steps in the table to install the LED Interface Module with the RCLA. 1. Clean the area near the connector using a cleaning solution and a soft cotton cloth. 3M Tar & Adhesive Remover is recommended.

2. Apply a small strip of high-strength doublesided mounting tape as shown. The tape is applied to a protrusion just above the cut-out for the wiring harness feed-thru.

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3. Press the rear combination lamp assembly onto the double-sided mounting tape as shown. Connect the vehicle connector, and re-install the grommet.

4. Install the LED Rear Combination Lamp Assembly per the Nissan Service Manual. There are two pawls/clips on the outside edge that must snap. Reattach bolts.

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5. Enjoy your new LED Rear Combination Lamp!

Figure 16. Completed Installation - STOP Mode

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4. Glossary A AWG BCM BJT COTS IC LED LH MOSFET MTBF mW MY RCLA RH RTV VDC W XOR

Amperes American Wire Gauge Body Control Module Bi-Polar Junction Transistor Commercial Off-The-Shelf Integrated Circuit Light-Emitting Diode Left-Hand Metal-Oxide Semiconductor Field-Effect Transistor Mean Time Between Failures Milli-Watts Model Year Rear Combination Lamp Assembly Right-Hand Room-Temperature Vulcanizing Volts, Direct Current Watts Exclusive-Or

5. References Carlson, A. Bruce. Circuits: Engineering Concepts and Analysis of Linear Electric Circuits. California: Brooks/Cole. 2000.

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