LED Flasher Negate All Hyperflashing?

[chamourian]

Just a hypothetical:

If you put LEDs in a stock system the lower resistance tricks the system into thinking the bulb has burned out. Fairly common knowledge. What if an aftermarket flasher designed for LEDs is installed, does it totally do away with the burned out light feature?

For example:

LED front signals but conventional bulbs in the rear. A rear bulb goes out; would you notice the loss?

Another example:
LED comes loose or breaks. No more light but would the system know that?

One thing to consider would be if a LED was to break, it would result in an open circuit, and therefore infinite resistance.

Possibly? Maybe? Who knows?

[scottmcphee]

Actually, it's reduced current flowing (not lower resistance) that triggers a stock OE flasher "burnt out bulb" mode, or hyperblinking while signaling.


LEDs require little current to work well. This low current is what triggers a normal OE flasher into hyperblinking because it thinks a bulb has burnt out. It mistakes the low current of LED for no current that a broken filament would cause. But an LED is properly connected there, it's just "undetectable" to the flasher.


Did you know hyperblinking only applies to signalling and not hazards? It's the same flasher controlling both. But when using hazard button on OE flasher with LEDs it will not hyperblink. (The bulb out feature is sidestepped for hazards.)


Did you know hyperblinking for burnt out bulb was an idea born in Australia, and later became an adopted standard around the world? I guess we can blame them!


Some people add load resistors to fix hyperblink while keeping OE flasher. What this does is fake-out having an incandescent bulb connected to the circuit. The flasher "thinks" (senses) a more normal amount (higher) current flowing, and does not trip its hyperblink when signaling. The OE flasher is now basically sensing a "load resistor burn out" and is ignoring the LED (wired in parallel). So if the resistor burns out (open) it will go into hyperblinking. Which maybe is a good thing, because load resistors can get VERY hot and can burn up and fail open. BUT if the LED were to burn out instead of the load resistor, the OE flasher wouldn't notice a bit, you'd have no hyperblink warning, and there'd be no light on that corner. So that's a fail.


Do away with load resistors. Invention: LED flasher. These too detect current flow but are tuned for lower current as to be expected from LEDs. Due to a variety of LEDs and things, LED flashers bring along compromises. Like a slow first blink to get out, or irregular sequence of first few blinks, or missing alarm/lock confirmation flash, etc.. as they try to "balance" and guess what is an appropriate LED load. And they may or may not indicate a burnt out LED with hyperblinking.


The challenges you describe (combo of incandescent fronts and LED rears...etc) are especially tough and can be quite hit or miss for proper signaling behaviour for these generic LED flashers.


I do know one LED flasher in particular quite well and how it handles such scenarios, and that is to never hyperblink. For any combo of incandescent or LED.