Re: LED headlight upgrade
 

Normally, the power for the fog light comes from the switch on the dash, through the fog light relay coil, then through the high beam filament to ground (and back to the battery via the chassis).

Between the fog light and the high beam filament is another (hot) wire connected to the high beam switch. When that high beam switch is closed, voltage is equal on BOTH sides of the fog light relay coil - NO difference in potential - and current through the relay coil stops and the fog light circuit opens. The path for high beam current comes directly from that high beam switch to the wire connected between the fog relay and the high beam filaments.

The substitution of an LED in place of the high beam filament changes the scheme significantly by increasing the resistance in the circuit significantly.

LEDs draw a tiny fraction of the current of their FILAMENT counterpart. And, their (forward direction) opposition to current flow (i.e., "impedance") is very low; so low that additional resistance or a current regulator is typically installed in series with the LED to allow it to work within its limited (current) parameters.

It is that current limiting additional resistance necessary for the LED that causes a problem for the fog lights. Where the headlight filament resistance may have been less than 10Ω to ground, the resistance in the LED path may be several 100s of ohms!

Solution: either install a (LOAD) resistor to ground with similar impedance as the original filament the LED replaced, OR provide a alternate path to ground for the fog light filament (relay).

LOAD resistor:

Restores the original control and functionality of the lights
Generates significant heat that has to be dissipated, when the high beams are on.
Adds external connections that are exposed to the outside environment

Alternate ground for the fog light relay:

Compared to the OE configuration, it reduces overall current draw when the high beams are ON
Results in the fog lights remaining ON along with the high beams*.

Re: LED headlight upgrade
 

Paul,

My question had to do w the utility of having the fogs on while driving w Hi Beams. Does it really make a difference when driving?

Re: LED headlight upgrade
 

Another new LED headlight product that should work for our cars. At $54.99 each, a real bargain!

Anyone willing to experiment?

http://www.ebay.com/itm/1-Xprite-60W...ZZLzX-&vxp=mtr

Re: LED headlight upgrade
 

Not a fan of the Lighted LED LEGO in the DRL mode yikes ! I hope Hansen gets these again everything is on backorder currently. GC

Re: LED headlight upgrade
 

Roadster, I never really answered your question.. Look at Paul's post 4-5 above mine, talking about how the fog lights and headlights work. my thing was to move the wire and add a relay I posted back a few pages, this will then detect when the high beam is on and use the relay to open the fog light circuit, turning the fog lights off when the high beams are on. then when low beams are on, the fog lights are on.

My biggest thing was to remove the load, yes our cars are fine with the OEM load, but any load I can remove at night is better, I will do the Relay mod when I pull the dash pad this winter, as I am doing other things too. this will prep me for LED headlights.

Re: LED headlight upgrade
 

No problem Jeff......just went out to the garage and tested.......
Park lights on....fog lights will turn on or off....
Headlights on....fog lights will turn on or off....
High Beams on.....fog lights will not turn on with switch.....if fog lights are on with low beam and switched to high beam....fog lights will automatically turn off and come back on when switched back to low beam....
IMO with these new headlights.....I don't feel the need for the use of the fog lights when using the high beams anyway as these are very bright.....very satisfied with the purchase.....:-D

Re: LED headlight upgrade
 

I forget did you buy genssi or Larsen?


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Re: LED headlight upgrade
 

I went with Larsen.....again very satisfied.....and the resistor works great....no cutting into any wires.....worked well for me....

Re: LED headlight upgrade
 

relay or resistor?

just confirming, my relay solution either cuts or moves a wire

Re: LED headlight upgrade
 

I went with Larsen as well I used the plug in adapter that superbrightleds sells. My foglight do not work with the high beams on. However the light from the LEDs are so superior I'm not really sure if that its really a problem. Also I test fit one of the LED headlights without the adapter and both lights new and old worked like they should. Not even sure if I needed it Jeff