Meta

Has anybody tried replacing the OEM Incandescent bulbs with LED replacement bulbs?

Did you need resistors (load simulators)?

Have any picks?

 

Meta

Nobody?

surfermsd

I cannot comment specificly on the frontier, but for every i car i have ever used leds lights in I have had to add a resistor.

Meta

I wondered about that. Were they recently manufactured cars. Did it cause a light out effect or blink really fast without the resistor? Thanks,

UKquest

The resistor is nothing to do with load simulation.

A typical LED operates at about 1.7v and is fully lit at about 25mA. There are others that operate at different voltages and require different currents. I'm using the every day regualr 10 cent red LED for this example.
Your car provides 13.8v and up to the limit of the fuse in any particular circuit, lets say 25A for exterior lighting, 10A for interior lighting.
As you can see, your LED will last about 1/10 of a second before its cooked.
Using Ohm's law you have 3 variables, Volts (V) current in Amps (I) and resistance in Ohms (R)

V = I x R
I = V / R
R = V / I

V = 13.8
I = 25mA

So now we have a value for V and I to fit in the above equation. Remember we are solving for R.
We already know the current, its 25mA, however we need to convert that to Amps which is real easy. 1A = 1000mA, therefore 25mA = 0.025A.

So: R = V / I

R = 13.8 / 0.025

R = 552 ohms.

Now, you need to make sure the resistor is capable of handling all this power. Well, yup, theres an equation for power too.
Power is called Watts, and the equation goes like this:

P = V x I

So, 13.8 x 0.025

P = 0.345W or 345mW (1000mW = 1W)

Resistors usually come in 0.1W, 0.125W, 0.250W, 0.500W, 1W + others.
For this circuit you need a 0.500W or a half (1/2) Watt with a value of 552 Ohms. Resistors only come in certain values and the closet you would find is 560 Ohm.

Bonus prize for working out how much current the Led will have with the new resistor value.


Before any of you ask, I design LED lighting systems + other electronics goodies.

 

Meta

Wow! There's an answer (allbeit a little heavy for me). Thanks. I was actually looking at some of these:
http://www.ledtronics.com/ds/aut3157
My assumption was that they combined a number of the "every day regular 10 cent red LED" such that the voltage was correct and the current was the only variable with a significan decrease (thus the possible need for load resistance). Further, since the flashers in newer vehicles are electronic (timed) and not thermal (load based), I would think the load might not matter. I don't know how the 'computer system' is tied into lighting loads though. Anyway... not to draw you into a conversation that would clearly be over my head, would you forsee issues in my using the linked light above?

UKquest

Well, I'm not sure if your vehicle has a bulb fail light on the dash. If it does then you might need the load, if not then I don't see the computer being connected to each bulb on the car. Buy one and try it without the load. Can you solder at all?

You are correct in that these bulb replacement modules work by having several LED's in series. Each one drops the voltage a little. Down side to this method is, if one fails, they all turn off. I'd design my circuits in parallel so if one fails, only one goes out. More expensive though.

Meta

Thanks for the reply. I can solder a bit. Yeah, that's kind of a bummer that they are wired like old Christmas lights. Hopefully they last a while in this application.