LEDmod
09-22-2006, 10:36 AM
LED swap on the Climate control isn't simple swap.
Cause of way circuit is designed, LED won't be that bright, so you'll have to redo the circuit so that they are more power..
This is for up to 2006, 07+ is little different..!!
I designed this to add a minimal load on the boards power supply and to balance out the LEDs and make them match the gauge cluster. I have tested this for one night and can find no adverse effect on the boards power supply. If I see anything out of the ordinary I will immediately post. I have calculated the circuit components and obtained datasheets for the power supply IC, so I am confident it is all in spec and properly designed. As with all of these DIY posts, I take no responsibility for anything (broken LCD, wife leaving you, meteor falling on your house, etc :P ) But I am a trainied electronics engineer and have taken the circuit effects into consideration. So here we go...
I will focus on the circuit design. I will note one thing though. Be VERY patient with the LCD. Use solder wick, and move from one end to the other so you are not focusing heat on one area too long. It will seem they will never come loose, but there is solder all the way through, so it takes a while to get it all out. Dont try removing it until you can see all pins on the bottom move when you wiggle the display.
First, the schematics I created of the circuit. The first is before modification and the second is afterward.
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/Schematic.jpg
NOTE!: I have not modified the schematic yet to reflect using the 330 ohm resistors instead of 220OHM. You can use either, but 330 balances the circuit much better. I actually use surface mount 1206 package resistors found on digikey or similar vendors. These match the surface mounts that you have to remove and dont require soldering an axial lead where a surface mount was before. But either will work.
Also, I reccommend doing the mod for the clock mentioned later in the thread no matter what. Some will work without, some wont, but they all will work if you cut the trace and add the 560 ohm and 1kohm resistor.
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/SchematicModified.jpg
I am just going to list out the components changed for simplicity.
1) Cut the trace between D307 and D308 (cathode, or negative of D307 to anode, or positive, of D308) with a sharp razor knife. Be careful not to damage other parts of the board and make sure it is completely cut.
2) Cut the trace runnig from D310 cathode (left side of board) to D316 anode (right side of board)
3) Cut the trace running from D312 cathode to D313 anode.
4) Connect the cathode side of D310, D308 and D307
5) Connect the cathode of D312 and D313
6) Replace R304 and R310 with 330 Ohm resistors
7) On the back of the board, replace R306 with a 330 Ohm resistor
8) Connect the Anode of D308 to one side of a 680 Ohm resistor. Connect the other end of this resistor to an 8V point on the board. I used the bottom side (the end away from D306) of R304. This is the part of R304 that connects to the trace running to the clock LEDs I wanted to use a 510 Ohm for the 680s I used , but was out of them. Can vary between 470 and 680 without a noticeable difference or issues with the circuit.
9) Connect the anode of D313 though another 680 Ohm resistor to the power supply side of R310 (the side NOT connected to D311).
10) Connect the anode of D316 to the same point as above via a 680 Ohm resistor.
11) Remove R307 and replace with a peice of small hookup wire. These may seem dimmer, but look perfect once you get the LCD back on since there are three of them lighting it
12) Test the board!
13) Clean all of your connections. Use something like a small knife to scrape off any flux (brownish colored stuff that is corosive) around solder joints and alchohol and a toothbrush to scub it. You can actually use water, but you need to blow it out and make sure it is completely dry before ever hookingit up. I reccomend alcohol for this application.
14) You will need to do a little carving on the faceplate peices that surround the LEDs so it will sit flush over the wires. The plastic is VERY soft, so this is easily done with a sharp knife. It takes some patience, but just keep at it until everything sits flat. I cover all my added wires with baby powder, press the faceplate down onto it, and use the marks it leaves on the back of the faceplate as a guide for cutting.
The LEDs will all (with exception of the clock) be running on approx 8 mA, which is a very safe value for them. They actually can handle much higher, but will be too bright and not look right with the gauges. From what I can tell we are adding about 25 mA or so to the original circuit load, which should be safe for the 7808 regulator that is running them. It runs nice and cool and should be in spec according to its datasheet. If I see ANY problems there I will post immediately, but do not see any reason to worry about that part. The resistors I calculated serve the purpose of holding the currents at a safe level as well as balancing out the brightness of all LEDs. As I mentioned, you can actually go lower (as I originally calculated) for the 680 Ohm resistors, but they look well balanced with them and current is reduced.
Tips for modifying the circuits:
1) You will want to test that the connections that are cut are actually broken using a multimeter to make sure you got them cut completely.
2) For running the new traces through the new resistors, I reccomend 1/16th watt axial lead resistors. I used 1/4 watt, but that was all I had on hand. 1/8th watt will be fine power wise and will be smaller. 1/16th watt would actually be enough, but harder to find.
3) I use the entire resistor leads for the wires. Adding wire only if necessary. I strip a long peice of small solid hookup wire and use the insulation to slide over the leads to insulate them.
4) Keep all leads as short as possible.
Here are the pics of the finished board before and after installation.
Right side:
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/ConsoleRightSide.jpg
Left Side:
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/ConsoleLeftSide.jpg
Clock:
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/ConsoleClock.jpg
Resistor on back:
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/ConsoleBack.jpg
And finished product
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/CC1.jpg
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/WZCC.jpg
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/GaugeAndCC.jpg
And my personal reccomendation for a finish (if you are old enough :P )
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/capn.jpg
**************EDIT******************************** *******
Thought I would move this part to here as I have had a lot of questions about it:
I came across something interesting during one of the console mods I performed the other night. When replacing the resistor in series with the clock LEDs, they ended up too dim. After doing some testing I figured out why. Due to tolerances in circuit components, the regulated voltage on that particular board was 7.90V as opposed to the 7.95V I have seen on other boards. This may seem in-significant, but the LEDs drop right at 2.643V each, adding to 7.93V. So simply replacing the resistor with a jumper allows for just enough voltage to power the LEDs and make them bright enough to illuminate the clock as long as the power supply is providing more than 7.93V. So, in the case of the one I mentioned the 7.90V causes major dimming issues. The LEDs barely light at all.
So, I added a quick fix, which is basically the same design as the other groups of 3 LEDs. I performed the following:
1) Cut the trace between the first LED and the second one.
2) Connect the Cathode of the first LED to the Cathode of the 3rd LED using a 1K Ohm resistor
3) Connect the anode of the second LED to the anode of the first LED using a 510 Ohm resistor.
So if anyone comes across this issue when trying this mod, this is why. I reccomend doing it this way the first time to avoid repeated disassembly and assembly. I will post pics of the next one I do this way to make it easier to follow.
Cause of way circuit is designed, LED won't be that bright, so you'll have to redo the circuit so that they are more power..
This is for up to 2006, 07+ is little different..!!
I designed this to add a minimal load on the boards power supply and to balance out the LEDs and make them match the gauge cluster. I have tested this for one night and can find no adverse effect on the boards power supply. If I see anything out of the ordinary I will immediately post. I have calculated the circuit components and obtained datasheets for the power supply IC, so I am confident it is all in spec and properly designed. As with all of these DIY posts, I take no responsibility for anything (broken LCD, wife leaving you, meteor falling on your house, etc :P ) But I am a trainied electronics engineer and have taken the circuit effects into consideration. So here we go...
I will focus on the circuit design. I will note one thing though. Be VERY patient with the LCD. Use solder wick, and move from one end to the other so you are not focusing heat on one area too long. It will seem they will never come loose, but there is solder all the way through, so it takes a while to get it all out. Dont try removing it until you can see all pins on the bottom move when you wiggle the display.
First, the schematics I created of the circuit. The first is before modification and the second is afterward.
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/Schematic.jpg
NOTE!: I have not modified the schematic yet to reflect using the 330 ohm resistors instead of 220OHM. You can use either, but 330 balances the circuit much better. I actually use surface mount 1206 package resistors found on digikey or similar vendors. These match the surface mounts that you have to remove and dont require soldering an axial lead where a surface mount was before. But either will work.
Also, I reccommend doing the mod for the clock mentioned later in the thread no matter what. Some will work without, some wont, but they all will work if you cut the trace and add the 560 ohm and 1kohm resistor.
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/SchematicModified.jpg
I am just going to list out the components changed for simplicity.
1) Cut the trace between D307 and D308 (cathode, or negative of D307 to anode, or positive, of D308) with a sharp razor knife. Be careful not to damage other parts of the board and make sure it is completely cut.
2) Cut the trace runnig from D310 cathode (left side of board) to D316 anode (right side of board)
3) Cut the trace running from D312 cathode to D313 anode.
4) Connect the cathode side of D310, D308 and D307
5) Connect the cathode of D312 and D313
6) Replace R304 and R310 with 330 Ohm resistors
7) On the back of the board, replace R306 with a 330 Ohm resistor
8) Connect the Anode of D308 to one side of a 680 Ohm resistor. Connect the other end of this resistor to an 8V point on the board. I used the bottom side (the end away from D306) of R304. This is the part of R304 that connects to the trace running to the clock LEDs I wanted to use a 510 Ohm for the 680s I used , but was out of them. Can vary between 470 and 680 without a noticeable difference or issues with the circuit.
9) Connect the anode of D313 though another 680 Ohm resistor to the power supply side of R310 (the side NOT connected to D311).
10) Connect the anode of D316 to the same point as above via a 680 Ohm resistor.
11) Remove R307 and replace with a peice of small hookup wire. These may seem dimmer, but look perfect once you get the LCD back on since there are three of them lighting it
12) Test the board!
13) Clean all of your connections. Use something like a small knife to scrape off any flux (brownish colored stuff that is corosive) around solder joints and alchohol and a toothbrush to scub it. You can actually use water, but you need to blow it out and make sure it is completely dry before ever hookingit up. I reccomend alcohol for this application.
14) You will need to do a little carving on the faceplate peices that surround the LEDs so it will sit flush over the wires. The plastic is VERY soft, so this is easily done with a sharp knife. It takes some patience, but just keep at it until everything sits flat. I cover all my added wires with baby powder, press the faceplate down onto it, and use the marks it leaves on the back of the faceplate as a guide for cutting.
The LEDs will all (with exception of the clock) be running on approx 8 mA, which is a very safe value for them. They actually can handle much higher, but will be too bright and not look right with the gauges. From what I can tell we are adding about 25 mA or so to the original circuit load, which should be safe for the 7808 regulator that is running them. It runs nice and cool and should be in spec according to its datasheet. If I see ANY problems there I will post immediately, but do not see any reason to worry about that part. The resistors I calculated serve the purpose of holding the currents at a safe level as well as balancing out the brightness of all LEDs. As I mentioned, you can actually go lower (as I originally calculated) for the 680 Ohm resistors, but they look well balanced with them and current is reduced.
Tips for modifying the circuits:
1) You will want to test that the connections that are cut are actually broken using a multimeter to make sure you got them cut completely.
2) For running the new traces through the new resistors, I reccomend 1/16th watt axial lead resistors. I used 1/4 watt, but that was all I had on hand. 1/8th watt will be fine power wise and will be smaller. 1/16th watt would actually be enough, but harder to find.
3) I use the entire resistor leads for the wires. Adding wire only if necessary. I strip a long peice of small solid hookup wire and use the insulation to slide over the leads to insulate them.
4) Keep all leads as short as possible.
Here are the pics of the finished board before and after installation.
Right side:
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/ConsoleRightSide.jpg
Left Side:
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/ConsoleLeftSide.jpg
Clock:
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/ConsoleClock.jpg
Resistor on back:
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/ConsoleBack.jpg
And finished product
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/CC1.jpg
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/WZCC.jpg
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/GaugeAndCC.jpg
And my personal reccomendation for a finish (if you are old enough :P )
http://www.scionlife.com/tech/images/center_console_led_replacement_tc/capn.jpg
**************EDIT******************************** *******
Thought I would move this part to here as I have had a lot of questions about it:
I came across something interesting during one of the console mods I performed the other night. When replacing the resistor in series with the clock LEDs, they ended up too dim. After doing some testing I figured out why. Due to tolerances in circuit components, the regulated voltage on that particular board was 7.90V as opposed to the 7.95V I have seen on other boards. This may seem in-significant, but the LEDs drop right at 2.643V each, adding to 7.93V. So simply replacing the resistor with a jumper allows for just enough voltage to power the LEDs and make them bright enough to illuminate the clock as long as the power supply is providing more than 7.93V. So, in the case of the one I mentioned the 7.90V causes major dimming issues. The LEDs barely light at all.
So, I added a quick fix, which is basically the same design as the other groups of 3 LEDs. I performed the following:
1) Cut the trace between the first LED and the second one.
2) Connect the Cathode of the first LED to the Cathode of the 3rd LED using a 1K Ohm resistor
3) Connect the anode of the second LED to the anode of the first LED using a 510 Ohm resistor.
So if anyone comes across this issue when trying this mod, this is why. I reccomend doing it this way the first time to avoid repeated disassembly and assembly. I will post pics of the next one I do this way to make it easier to follow.