Xtralights HID Conversion Kit
Maybe the wiring on a 22 year old car gains resistance over time? Dunno. Just doing my happy dance for not having to jumper the relay.
The Best of Corvette for Corvette Enthusiasts
Maybe the wiring on a 22 year old car gains resistance over time? Dunno. Just doing my happy dance for not having to jumper the relay.
I am glad it worked without any mods for you
The price is great! I tried to find the wattage or current draw but they do not list it. The current draw would give a clue if they have a built in resistor. If the high beams are on and they have resistors in parallel to the LED (diode) they will draw more current than an LED without the resistor.
So it has nothing to do with 22 year old wiring gaining resistance (resistance would have to decrease and a wire cannot do that over time).
Last edited by grandspt; Nov 21, 2017 at 05:38 AM.
Hook 'em up and let us know!
I am glad it worked without any mods for you
The price is great! I tried to find the wattage or current draw but they do not list it. The current draw would give a clue if they have a built in resistor. If the high beams are on and they have resistors in parallel to the LED (diode) they will draw more current than an LED without the resistor.
So it has nothing to do with 22 year old wiring gaining resistance (resistance would have to decrease and a wire cannot do that over time).

Anyway, very glad I resisted the urge to mod the relay while waiting for UPS.

Without cutoff some lights are for off-road use only. Those particular lights appear to be the off-road type. Cost is the first thing you'll notice; off-road typically cost 1/10 as much as DOT approved lights.
Without cutoff some lights are for off-road use only. Those particular lights appear to be the off-road type. Cost is the first thing you'll notice; off-road typically cost 1/10 as much as DOT approved lights.
So if you add an incandescent bulb in a parallel circuit to the LED light you are decreasing the resistance across the LED.
If you add the incandescent bulb in series circuit to the LED you are increasing the resistance of the LED.
Conclusion: The LED headlights you have must have a resistor (or maybe even a hidden incandescent bulb inside the housing) in parallel to the high beam LED circuit. This allows your fog light relay to work without a modification.
I hope I didn't confuse things as that was not my intention.
One should understand the operating parameters of the original (incandescent) bulb(s) and those of the LEDs are practically opposite one another, leading to special circuit considerations:
incandescent (filaments) bulbs are have relatively low resistance and thus pass a lot of current which is required to heat them till they glow (white-hot)
Light Emitting Diodes (LED) chips, on the other hand, require very little voltage (as little as 0.6V) to switch them ON. But, here's the rub: once they're switched ON, they have very low resistance and would easily be burned up when (12 volts) is applied.
So, LEDs intended for automotive use are pre-packaged, often simply large value resistors (ed) connected in series with the LED (chip) itself, drastically reducing current flow . This current reduction reduces the load on the electrical system significantly.
So...what's the issue??
Often there are relays and other components, e.g., turn signal blinkers, etc., that depend on that higher current draw to function. By simply swapping out various bulbs for LEDs there can suddenly be a number of unintended changes and how the circuits now work...or NOT work!
Two solutions:
Replace the standard "blinker" switches with LED (electronic) blinker switches: These blinkers solve many of the problems encountered when swapping the old bulbs for LEDs. However, the old blinkers would fail to work if a standard bulb were to go out, but most electronic "LED" blinkers continue to function, with or without bulbs in the circuit.
LOAD resistors: Substituting and including a LOAD resistor with the LED installation will simulate the original (filament) current draw and will return most circuits to their original operational configuration, e.g. Fog lights "issue":
By design, if the fog light switch is turned ON, the fog lights will be illuminated until the headlights HIGH beams are turned ON. (Don't ask me what the logic was for that...unless there was some law or designers were attempting to limit system current draw??).
IF it is desired to have the lights work as designed (say for originallity/NCRS perhaps?), either a LOAD resistor will be needed to provide a low resistance to ground so the relay will work, OR a more sophisticated relay circuit (beyond the scope of this post) can be used instead of the LOAD resistance.
However, as many have pointed out, simply grounding the fog lamp relay will result in the fogs being on anytime the fog switch is ON, regardless of whether the high beam switch is ON or OFF. This simple step is easy and cheap to do and my be preferable to most. And...if an LED bulb is substituted for the old bulb, the over-all current load will be reduced in spite of the fogs being ON (along with the LED high beams).
If the marker lights are converted to LEDs, the fact that LEDs only conduct current in ONE DIRECTION ONLY creates yet another set of circumstances and need of a special circuit. But, we're way beyond explaining headlight/fog light and relays. So, for now perhaps maybe consider not to change out those old bulbs?
Anyways... These are the basic considerations one might use when considering replacing the old bulbs with the more efficient (AND BRIGHTER) LEDs.
Lots of ways to skin this cat!
Last edited by Paul Workman; Nov 22, 2017 at 10:07 AM.
IF it is desired to have the lights work as designed (say for originallity/NCRS perhaps?), either a LOAD resistor will be needed to provide a low resistance to ground so the relay will work, OR a more sophisticated relay circuit (beyond the scope of this post) can be used instead of the LOAD resistance.
However, as many have pointed out, simply grounding the fog lamp relay will result in the fogs being on anytime the fog switch is ON, regardless of whether the high beam switch is ON or OFF. This simple step is easy and cheap to do and my be preferable to most. And...if an LED bulb is substituted for the old bulb, the over-all current load will be reduced in spite of the fogs being ON (along with the LED high beams).
Last edited by PatternDayTrader; Nov 21, 2017 at 09:41 PM.
Gary
So if you add an incandescent bulb in a parallel circuit to the LED light you are decreasing the resistance across the LED.
If you add the incandescent bulb in series circuit to the LED you are increasing the resistance of the LED.
Conclusion: The LED headlights you have must have a resistor (or maybe even a hidden incandescent bulb inside the housing) in parallel to the high beam LED circuit. This allows your fog light relay to work without a modification.
I hope I didn't confuse things as that was not my intention.
As should be expected, I buy something fun for the 'vette then something of equal or higher value fails. Getting a MAF error code P0100.

So it goes.















