So i'm in the process of changing out all my incandescent bulbs to a more stylish LED scheme. One of the problems i've run into is the "hyperflash" when you change your turn signal bulbs. I've searched for answers, but most of the threads i've found were several years old. I'm hoping more options might have popped up which weren't discussed.

So far, i've only changed my rear turn signal bulbs. Now that it blinks faster, i'm guessing that if/when I change my front turn signals, it will flash even faster. I've been researching on ways to "fix" this problem, and have seen 2 solutions:

1 - Using a load resistor

or

2 - Using a LED Flasher relay

With the load resistor, I have read that you will need to tap 1 resistor to each line an LED is being used. I also read that it generates A LOT of heat...enough to melt plastic.

With the LED flasher relay, it plugs into your old relay, but lets you run LEDs on your vehicle without causing error codes or "hyperflash".

Does anyone have it setup with the load resistors? Does it really generate that much heat? What did you mount it to?

From my research, it seems that the LED flasher relay would be the most efficient way to go, but I've never seen a specific part for our SC430s. Does anyone have one of these relays?

 

I've always avoided messing too much with the electrical system on my cars that are highly computerized. Experienced service managers have confirmed this to me. Often things will work fine and then various lights and other electrical functions start to act up. This is especially common with aftermarket remote starting systems.
This does not always happen, of course, so you are taking your chances. For my thinking, if the outcome is simply to be "stylish," I would rather be old fashioned and rolling down the highway than be way cool and sitting by the side of the road, especially when the incremental style element is so small as to be imperceptible.
I changed my interior lights to LED for the added illumination (a nice touch in the trunk, especially, and on the bottom of the doors), but have not added LED headlights, fog lights or tail lights.
What if you didn't change the blinkers to LEDs and just told people you did?
Works for me.

 

The turn signals in cars have long had sensing circuitry that looks for a burned out bulb. When it senses that a bulb has burned out, it will speed up the flash frequency to give the user an indication that there is a problem and most likely a bulb burned out. (Basically, it senses that the low impedance bulb has gone to high impedance or "open".)

Adding a resistor in-line will generate a lot of heat just because it is replacing the bulb that does the same. This method will not save on any power burned, if that is part of your intentions here. There might be some "active" loads available that wouldn't get hot, but since I've never looked into it, I can't make any recommendations.

Good luck.

 

Harold:
Does that mean that an LED with resistor would render inoperative the dashboard warning that the turn signal lamp is not working?

 

Honestly, the other option I had was to change the rear turn signal back to the standard incandescent bulb because there wasn't really too big of a difference, but I know that when I do change out my front turn signal bulbs, I will run into the same problem which is why I wanted to know if someone had a solution for this.

I don't really need to change any of the rear tails into LED. I don't think anyone else besides me would notice anyways.

 

On the SC (well....i should say on my SC), changing out the turn signal bulb did not throw up a dashboard warning light. The "hyperflash" itself is the warning. When it flashes fast like that, it usually means that a bulb is burned out somewhere.

I did change out my dual filament brake lights, and that ended up putting a dashboard warning light. From what I read, load resistors that tap into the lines will solve both of these problems because it mimics the load that a regular incandescent bulb puts out. The only problem that i've read about is that these load resistors generate heat like the light bulb it's replacing, so it has to be mounted to metal. I've read that a higher rated wattage load resistor would make it so it doesn't get as hot, but i'd like to know if anyone had any first hand experience with load resistors.

 

The 06 taillight upgrade uses LEDs for brake and tail lights and is a nice update to the appearence of the car IMHO. The turn indicator light remains an incandescent bulb. I changed out the yellow tinted bulb to a chome one which is amber when lit. By going with the chrome bulb you eliminate the egg yoke affect when the bulb is off. I did try amber LEDs but found their brightness, or the number of lumens cast, sorely lacking when lit.

 

So with the 06 taillight upgrade, did changing over to the LEDs cause the dashboard warning light to come on? If so, did you have to use a load resistor, or does the housing of the 06 taillight have some sort of built in feature?

 

The 06 upgrade replaces both taillight assemblies and wire harnesses. If you go the full boat, you also replace the ECU in the trunk and you don't get an fault indicator light. Others have opted not to replace the ECU due to the cost. Instead they chosen to go with a piece of black tape over the instrument panel light out indicator. Either way the 06 tails look a lot nicer to me.

 

But if you go "full boat" and replace the ECU in the trunk, which turns off the fault indicator light on the dash, and then the tail light later faults, will the fault indicator light indicate a fault or will it read the new ECU and think everything is fine back there?

 

The indicator light comes on when there is a change in expected voltage, i.e. an incandescent filament burns out. If you replace the 02-05 tails with the 06+ LED tails the 02-05 ECU detects a voltage change and illuminates the instrument panel light indicating a taillamp problem. The 06+ ECU is correctly calibrated for the LED voltage thus no indicator lamp is lit on the instrument panel until such time as a LED failure.
Since LEDs have such long MTBF lives, I've personally never tested it. And, each LED taillight lamp actually consists of several, well, .... LEDs not just one filament in the case of the incandescent bulb. Thus if one LED segment fails the remaining ones continue to function properly. An example of this are LED traffic signal lights. As the segments begin to fail strange patterns begin to form however, the remaining segments continue to work fulfilling the light's purpose.
I suppose I could disconnect the wire harness, so none of segements light and see if the "fault indicator" light illuminates on the instrument panel to test it. Or, just not worry about it.
Since the OP was asking about LEDs and the hyperflashing it caused with the turn signal indicator I thought it was interesting that Lexus did NOT convert the incandescent turn indicator lamp to LEDs at the same time as the taillights. It tells us something...we just don't know what.

 

Since LED failure is very rare, and since there are multiple LEDs in a taillight assembly, the question of whether the fault warning on the dash still functions is mostly academic anyway. It would be nice to have LEDs for the taillights and brake lights, but to me the hassle involved does not justify the almost imperceptible result.

 

IMHO the LED tails are a technological and safety feature improvement. I also believe they are brighter than the incandecent ones. Two screws and a couple of pressure clips are not much of a hassle to me. But changing out the ECU does take some effort getting the trunk apart.