Anyone good with electronics and wiring? Switching a halogen bulb on a circuit board to an LED bulb

Chris

Chris

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I've currently got my factory Rubicon locker switch (the one mounted on the dash) apart. The bulb that illuminates the switch is a 14V 100ma halogen bulb, but it's soldered directly to the circuit board. I removed it and plan to solder on an LED bulb in it's place.

These are the LED bulbs I ordered to replace it:
https://www.amazon.com/gp/product/B01AUI4VVA/?tag=wranglerorg-20

I put one on in place of the halogen bulb, plug the switch in, turn on the interior lights, and it lights up for half a second, then "pops" (as in it blows the LED).

So clearly I'm not smart enough with electronics to know what I'm doing wrong. I know how to solder really damn well, but I must be using the wrong type of LED bulb to replace it will.

I'm hoping someone on here is good with electronics and can tell me what kind of LED bulb I need to use as a replacement for the halogen bulb.
 
Okay, so I've been doing some reading, and it appears that since this is a 3V LED, it's popping because the amount of voltage being fed to it is somewhere around 12V (makes sense, since that's what the battery in the vehicle is). That being said, it seems that maybe what I need is a resistor (not sure what resistor), or something like these:

https://www.amazon.com/dp/B074SKDD5C/?tag=wranglerorg-20

Those apparently work up to 12V and have a built in resistor.

If anyone knows anything about electronics, please tell me if I'm wrong.
 
Chris said:
Okay, so I've been doing some reading, and it appears that since this is a 3V LED, it's popping because the amount of voltage being fed to it is somewhere around 12V (makes sense, since that's what the battery in the vehicle is). That being said, it seems that maybe what I need is a resistor (not sure what resistor), or something like these:

https://www.amazon.com/dp/B074SKDD5C/?tag=wranglerorg-20

Those apparently work up to 12V and have a built in resistor.

If anyone knows anything about electronics, please tell me if I'm wrong.
Click to expand...
You were already given a solution, no?

"You need to add a resistor to bring the voltage down from 14 to the 3V that your LED wants. From ohms law, R = (V1 -V2)/ L. In your case R = (14V - 3V)/ .02amp. So you need a 550 ohm resistor in the circuit.

Here is a link that can help give a better explanation.

http://www.instructables.com/id/LEDs-for-Beginners/"
 
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TomTJ said:
You need to add a resistor to bring the voltage down from 14 to the 3V that your LED wants. From ohms law, R = (V1 -V2)/ L. In your case R = (14V - 3V)/ .02amp. So you need a 550 ohm resistor in the circuit.

Here is a link that can help give a better explanation.

http://www.instructables.com/id/LEDs-for-Beginners/
Click to expand...

I don't know how I missed your post, thanks a million!

This is what I was stumbling upon as well, that I needed a resistor. Does that resistor then get soldered inline with the positive leg of the LED bulb?

I've also noticed 550 ohm resistors seem to be hard to find.

Is there an alternative resistor I could use that might be easier to find?
 
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Chris,
The resistor can go anywhere in the circuit (pos or neg side). If you can’t find 550 ohm, look for a bit larger ohm value.....that should be fine. You can also add multiple resistors in series and you just add the ohm value in that case. So two 250 ohm and a 50 ohm would give you 550.
 
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TomTJ said:
Chris,
The resistor can go anywhere in the circuit (pos or neg side). If you can’t find 550 ohm, look for a bit larger ohm value.....that should be fine. You can also add multiple resistors in series and you just add the ohm value in that case. So two 250 ohm and a 50 ohm would give you 550.
Click to expand...

Maybe I'll just order one of these:
https://www.amazon.com/dp/B072BL2VX1/?tag=wranglerorg-20

That has a 470 ohm and a 100 ohm, so I could wire those in series and get 570 ohm.

The issue is that the space I have to work with is very small (being as though it's inside of the Rubicon locker switch), so I think I could probably get two resistors in there, but not more than that.
 
550 OHM resistors are going to be almost impossible to find for your application, you'll need to come close with "in series" resistors.
 
CodaMan said:
550 OHM resistors are going to be almost impossible to find for your application, you'll need to come close with "in series" resistors.
Click to expand...

Yeah, that's what I'm going to have to do. I'll wire a few in series on one leg of the LED. I'll probably end up a bit over 550 ohm.

Oh... I'm going through all this effort BTW, because I changed out all of my interior lighting bulbs to LED, but the locker switch illumination now doesn't entirely match the other switches (which have easily replaceable bulbs), so my OCD won't let this one fly.
 
Chris said:
Yeah, that's what I'm going to have to do. I'll wire a few in series on one leg of the LED. I'll probably end up a bit over 550 ohm.

Oh... I'm going through all this effort BTW, because I changed out all of my interior lighting bulbs to LED, but the locker switch illumination now doesn't entirely match the other switches (which have easily replaceable bulbs), so my OCD won't let this one fly.
Click to expand...

Don't you just love OCD? hahaha
 
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Try the 570ohm. That should give 570 = (14 - V) / .02amp. Solving for V we have 14V - (570) (.02) = 2.6V. That should be enough to light the LED, especially if you are getting more of 14.2V from the alternator. With the non-standard values, and the variable voltage for individual cars, you gotta play with the values to see what works. If its too dim, replace the 100ohm with a 50 in your series.

Before going through the hassle of installing it in your switch, just connect it together and test it to insure it works (just put it across the battery terminals when the Jeep is running).
 
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TomTJ said:
Try the 570ohm. That should give 570 = (14 - V) / .02amp. Solving for V we have 14V - (570) (.02) = 2.6V. That should be enough to light the LED, especially if you are getting more of 14.2V from the alternator. With the non-standard values, and the variable voltage for individual cars, you gotta play with the values to see what works. If its too dim, replace the 100ohm with a 50 in your series.

Before going through the hassle of installing it in your switch, just connect it together and test it to insure it works (just put it across the battery terminals when the Jeep is running).
Click to expand...

Solid advice, I'll do that. I can connect some long wires to the ends of the LED and run them to the positive and negative on the battery to test. I'll play around with the resistors to see which combination gives me the right amount of light. It doesn't need to be tons obviously, but it needs to be enough to light the switch up as well as the others.
 
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