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Discussion Starter · #1 · (Edited)
Like others I have wondered why in the world Sonata gave us FOG lights that could not be independently turned on. FOG lights are designed and intended to be used in a very specific situation and in general should not be white either. To solve this IMO shortcoming I just finished modding my light system so I now have the option of turning on just my FOG lights w/o having my low beams on. My mod also retains the full HIGH beam OEM option when only having the FOG lights on. I won't go into all the details and this mod is best done if you have installed the HID aftermarket LOW beams and used the accessory wiring harness to power your aftermarket HIDs so the rest of this is based on that configuration. This mod requires NO MODIFICATION or doing anything to any of the factory wiring and only requires either one switch or as an option the addition of one $5 relay.

The basic mod is based on interrupting the coil power to the power relay in the aftermarket accessory wiring harness that powers the HID low beams. My HIDs are from XS and use their accessory wiring harness, but other makes should basically be similar where the power for the HIDs comes directly from the battery thru a new relay that is activated by the factory LOW beam voltage which is used for the HID relay coil. I won't get into a lot of details on exactly now to do this because there are several ways to accomplish this and one should IMO have enough electrical knowledge to make the necessary mods and wire things up given just the basics or they should not be attempting this at all.
The switch only option simple require you to put a switch in line with either the +12V or ground wire on the aftermarket power relay coil. I would recommend putting it on the ground side and at least for the XS harness the coil ground is not referenced to the chassis ground, but is the ballast ground so you will have to run two wires for your switch.

I opted for the switch plus an additional relay just to keep the amount of extra wire added to the circuit I was modding down to a minimum. I used one of the Radio Shack mini/micro SPDT 12V PCB relays mainly because I had some laying around and are very small. I used the NC side of the relay to break the +12V power wire to the HID power relay and used the +12V from the battery side of the HID power relay for my new +12V coil power and used my new switch to control the chassis ground for the coil power. Thus the normal static state of the new relay runs everything normally. When I energize the new coil by connecting the chassis ground thru my new switch the coil is engergized opening the relay contacts and cutting power to the HID power relay coil and turning off the HID headlights while leaving all the other lights on which are controlled by the factory column switch. In fact I now have the option in addition to the regular running lights of NORMAL LIGHTS, FOG LIGHTS ONLY, HIGH BEAMS ONLY, and FOG LIGHTS WITH HIGH BEAMS.

Here is a pic of my new light switch which I mounted to the side panel of the center console with double stick tape. It is out of the way so you won't accidently hit the switch, but still convenient when needed.



To see if you even want to consider this you can simply pull your HID power relay which will prevent your LOW BEAMS from coming on and you can see if using just your FOG lights would be an option you would want. I found this could be useful at lower speeds especially since I upgradeed my factory lights to the PIAA YELLOW PLASMA FOG light bulbs.

Larry
 

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I have no fog lights on my 08 Tucson. Is the dash prewired for a OEM rocker switch in the event I install fog lights?
 

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I have no fog lights on my 08 Tucson. Is the dash prewired for a OEM rocker switch in the event I install fog lights?
You don't want fog lights. One of the most useless add ons on any vehicle. All that happens is that the light is reflected back off the fog and you cannot see anything then. Also the number of people that "forget" that they have their fogs on is unbelievable. I will admit that the above only applies to front fogs. Rear fogs are a good idea unless the user "forgets" to turn them off.

More to the point this thread is 7 years old. Might be better to start a new one. That's where the "moderator much vaunted search function" falls on it's backside.
 

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Totally disagree. Point of fog lights is to get under the fog. Fog typically is not found right on the ground. In foggy conditions, low hanging fog lights will illuminate much further than headlights that are higher above the ground. I will probably just get a pair of descent after mart glass fog lights and hang them as low as possible.
 
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