When I purchased my car, I noticed the clock did not light up. I read thread after thread of others having the same issue. Most just got a new clock under warranty. There is very little info out there on possible fixes. Well, last night, I decided to try my hand at solving this problem.
Inside the clock, there are 4 springs that connect the pins from the plug to 4 pads on the circuit board. I read that the springs may have become compressed not allowing contact so the lights do not illuminate. Took the clock apart and the springs appeared to have a good connection. Bummer.
Thankfully the 4 pads on the board are labeled so I knew which ones were + and – for the illumination. I then figured out which pads corresponds with the pins in the connector and then to the harness in the car. Tested to make sure I was getting voltage. I was, and the voltage dropped when dimming the dash. So far so good.
Next, tested the LEDs (before removing them from the board) and the LEDs were indeed bad
. Not the end of the world, I will just replace them.
Removed the LEDs and using a multimeter tried to figure out which LED contacts (on the board) were + and which were -, I did not simply want to rely on the cathode mark on the LED. Long story short (I will not bore you will all the details I learned), it seems that neither the + nor - pads where power is supplied on the board are connected to the pads where the LEDs are soldered on…. at all.
This was a real downer, it seems that the circuit board is bad… at least for the illumination.
So here is what I did….. I first covered the + pads where the LEDs go with electrical tape (I did not want to re-introduce power to the board) and soldered the - side of the LEDs to the board. Added a resistor to the + side and simply ran wires from the LEDs to the pads where the springs connect. (Go ahead, make fun of my solder joints.... this stuff is TINY! lol)
Now my clock lights (and dims)!!!
It's little too bright. I may replace the resistors with a higher ohm version to get the brightness closer to the rest of the dash. I wish I knew the wavelength of the blue/purple OEM LEDs. My guess would be low 400s. I may just get this to scavenge the lights! 10-15 INFINITI EX35 G37 QX50 AUDIO INFORMATION CONTROL PANEL UNIT CC4774 | eBay