Well, I have been going over this low voltage issue with the center console blue LED conversion and think I might try this idea.( First, the problem is the Blue LED's require 3.3v min to operate full bright. The center console only gets around 2.6v. This is plenty for amber, green, red, etc. LED's as they operate from 2.2v and up.

On the dash side cluster is the pot to adjust the brightness of the gauges and console. As resistance goes up, the lights dim down. As resistance goes down, the lights go up.

I wonder if I measure the resistance of the pot from low to high, then solder a resistor in parallel dropping the resistance on full brightness just a little to provide 1 more volt on full brightness....would this work?

For example, if the low side (high bright) was 100 ohms. If I place another 100 ohm in parallel it would be a 50 ohm drop. By formulation, I should be able to make it 80 ohms and still be safe.

Any thoughts

 

Yeah but wouldn't this increase the voltage to the gauges as well? They seem to be fine. Someone on this board (Dolphan2k) posted that he/she up'd the voltage on the console by changing a diode near the console's power transistor but I haven't got a single response from them at all and it's be like 3 weeks, so I'm calling BS on their solution. In theory though there must be a way, and the answer is on the console. Maybe a new power transistor that supplies more voltage.

I'm thinking about getting a salvaged console from a wrecked tC but there isn't many (if any) is this area, so supplies are limited. I'd love to experiment with one to find the solution or get a hold on the schematics.

 

Yea, if he can't produce results...BS is in order

Yea, you're right it would increase the gauge voltage as well...

Yea, a spare one to work with would be great, a schematic would be perfect.

Tell you what, The console is where the problem is and is much easier to pullout and get to the electronics. I'll pull it and search the transistor to see what it is now, and what would be a minor V upgrade.

Funny thing, when you push the A/C button, the LED indicator is bright. Same with the other. Same for you?

I can live with it...but I don't like it because it's not right

 

You could also use a variable regulator... they make a variation of the popular old LM7405 (only a couple of bucks) that is variable... cant remember the part number off hand.. 7415 maybe? A little interfacing work from the pot on the dash could provide the variable voltage control, and the regulator supply could be powered via the 12v source. This would keep it from affecting the rest of the dash lights, and would provide power for any other LEDs you would want to add later. At work right now, so I dont have time to go through the calcs for it... but can try to do it later.

I am thinking your idea with the parallel resistor would work, but would effect the rest of the circuit. However, as the total applied voltage would be the same, it should only shift the dimming in relation to the pot setting if that makes sense... I will have to look at it when i have more time to figure that part out.

 

The other issue with providing more voltage to everything would be that a lot of current would be dissipated in the other LEDs (the low voltage ones). But you could simply find the supply to them and solder in the proper resistor to drop the excess voltage.

 

That is an outstanding approach

 

This whole Blue LED dim thing sucks Really strange how the gauges are perfect, but the console is dim with the exception of the indicator lights on a few switches when activated..... Like AC

I have searched the internet over for lower voltage Blue LED's. Fairchild has 2.6v B;ue LED's for cell phones they just created...but they are 90 deg angle led's.

 

Yeah I wish I could find out where we could get the blue led's that are the exact same as the temp **** one. My thoughts on that are they are on seperate circuitry from the ones that backlight the LCD and buttons. I was told by someone, I can't remember who, that when they took out one of the led's behind the lcd, the other two were brighter. They used a piece of wire to bridge the contacts of the one that was removed.

We should also look at the amperage as well, the led's I have are rated 98mcd @ 20mA. If by chance the stock one's use less amperage, say maybe 10mA.... I dunno, maybe I'm on to something or I'm just talking out of my ___ at this point just trying to grab an idea.

 

The guy that jumpered behind the LCD after removing the middle led...did it make all of them brighter, or just the 2 in that circuit?

As my last option, I will get some BLUE LED's, glue (epoxy/whatever is none conductive) them to the circuit board where the existing surface mounted chip led's are. 90 degree ones would be perfect because the LED would be facing up and their leads would be out the side. Check these out

http://www.ledtronics.com/ds/rab362/Default.asp

Run the feed out to a 12v source that comes on when the console is lit up. I would get a pot to control the LED's like the dash...mount that in the cubby hole or under dash or something so if I ever wanted to dim it, I could.

If I can't get a resolution for this soon....I will brighten it up this way.

 

The frst link is the circuit board and the 2nd the board is lighted. The LED's in the center I did not change (temp ****).


https://www.scionlife.com/tech/illum...ange_tc/12.jpg

https://www.scionlife.com/tech/illum...ange_tc/13.jpg

 

One thing I forgot to ask before.... Is the power source for the LEDs designed for the exact voltage, or is it , say 5V with a resistor before the LED to drop the voltage, as is the case in many circuits. Then we can just find the resistors on the board and swap them out to change the control voltage. Just use R = (Vs - Vl)/I, where R = the resistor rating in ohms, Vs = Value of the voltage source, Vl = the forward voltage drop of the LED, and I = forward current rating of the LED in amps.

I am guessing that someone has already checked into this, but it was worth bringing up.