I kind of am all over the place with this and I would like to firstly apologize if this isnt in the right place…I created a forum looking for the correct SMD LEDs for my shift knob on my car. The original forum is here… What are these LEDs called?
After ordering the small blue LEDs I got to installing them! I did install the white LEDs in replace of the orange that was on the shift knob and those worked perfectly. I did the same thing on my cluster along with my radio. I even replaced the small green LEDs with the blue and they worked perfectly fine. For some reason when I did these ones though the lights turn on for a second when I start my car and then they turn off. I decided to take the LEDs off and test them with my multimeter and they all turned on. So there was no dead lights. I then thought they were too powerful so I decided to try ones with a lower current. Again they turn on for a second and then turn off. The 2 blue lights would be on when I turn the car on because it would indicated its in park. Then when shifting to reverse, drive, ect the lights would turn off and then only 1 should come on. But its like the current starts and then at some point it just dies. I will include a video of my starting the car and you seeing the lights on, then shutting off. I am absolutely positive the polarity is correct as I have cross checked my original picture of the board and made sure. Soldering them on twice as well to make sure and all the lights work. My question is how would I test resistors or capacitors with my multimeter? Should I have it on a specific setting? Maybe someone will know my issues and point it out…but I am stumped. I would like to mention that the very first time I did install these small lights that the polarity on the second LED (the blue one on the right) was actually backwards. From my research that didnt seem like it should be an issue other than the lights just not turning on. But since its a contant current when the car turns on would it kill something? Im sorry for the long response and if this is in the wrong area. I feel like I need new resistors maybe? I will include both sides of the small circuit board, along with the video, and my multimeter if someone can help where I should start. I absolutely LOVE the digikey products and I will continue purchasing them…I just know I made an error somewhere here. The video is blurry of it turning on and off but I will include pictures of the actual board so you can see it clearer.
This is it turning on and off
If the LEDs turn on each time you start up and then turn off, they should still be functional. To test if your circuit is still good, you could try putting your original LEDs back on and seeing if it works as it did before you replaced them. If so, then it’s very hard to say what’s going on. Perhaps a component on another board on the other end of that cable senses too much current draw with the replacement LEDs and shuts it down. If not, then some component(s) may have failed.
It might help you to figure out the current paths of those LEDs, so you know which circuit traces and resistors are in series with them. You can do this by looking carefully at the traces on the board and following where they go. Assuming the continuity mode on your multimeter is functional (see how to do that here), you can use it to identify which points on your board are shorted together, thereby figuring out the circuit connections. No offense, but your multimeter looks pretty sketchy, so it may or may not work for that.
Your meter has no capability of testing capacitors, though you only have a few on that board and they are unlikely to be bad. To get a truly accurate measurement of a resistor, it should be removed from the board and tested by itself. However, for the purposes of testing whether they are still good, you generally don’t have to remove them. Just set your multimeter to the right resistance range and place one lead on each end of the resistor. If it is good, it should measure somewhere fairly close to the value printed on it. For instance, the resistor with 1001 printed on it should measure close to 1000 Ohms. If it has failed, it is likely to measure much higher, as resistors generally fail open circuit.
The way to interpret the value of the resistor is to write all but the last digit down and then place the number of “zeroes” specified by the last digit behind that. An “R” represents a decimal point.
So for instance a marking of:
- “33R0” ==> “33.” followed by zero "0"s ==> 33.0 Ohm
- “810” ==> “81” followed by zero "0"s ==> 81 Ohms
- “1001” ==> “100” followed by one “0” ==> 1000 Ohms
If the resistors are all good and your circuit works properly with the original LEDs, then you may try increasing the value of the resistors which are in series with the LEDs in question. You might try a value 50% to 100% higher, which would likely have the effect of reducing the current through those LEDs (also making them dimmer of course). If my above speculation of overcurrent is correct (pure speculation, I might add) then that might work. Hard to say.