the moment you've been waiting for, Foglight switch modification
04-05-03, 05:01 PM
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the moment you've been waiting for, Foglight switch modification
Brought to you by BananaGS 
Many of you have asked for this mod, so here it is.
Turn on your OEM fog light anytime you want using the factory switch. (GS300/400 only) (probably work with other Lexus, except you will have to locate the foglight switch signal yourself)
took me 4-5hours, I think this is the simplest way to do it.
I took many things apart to find a simpler way to do this for you (that is why It took me so long), but have not find an easier solution, there you have it.
if you follow the instruction on my page, probably take you 1-2 hours to do.
Anh
Many of you have asked for this mod, so here it is.
Turn on your OEM fog light anytime you want using the factory switch. (GS300/400 only) (probably work with other Lexus, except you will have to locate the foglight switch signal yourself)
took me 4-5hours, I think this is the simplest way to do it.
I took many things apart to find a simpler way to do this for you (that is why It took me so long), but have not find an easier solution, there you have it.
if you follow the instruction on my page, probably take you 1-2 hours to do.
Anh
Last edited by BananaGS; 04-06-03 at 08:45 AM.
You never cease to amaze me dude!! 
04-10-03, 11:57 PM
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Banana,
There are easier ways. I've never had the time to photo and document the method in detail, but perhaps you can? This took about 20 minutes.
Here's two old posts I made:
A: Fogs with High and Low beams - Tested
Sorry no pictures and not too many specifics but this works:
Connect a 1 Amp diode between pin 14 (Red with Black strip) and pin 11 (Green with Black stripe) on the headlamp switch connector, with the + end of the diode connected to pin 14.
This grounds the fog relay when the headlight relay is grounded. To protect from installation mistakes put a 1 amp fuse (optional) in series with the diode. Power comes to the existing 15A fog fuse directly from a 120A fuseable link so no fear of overload.
BEWARE; MISTAKES CAN MELT WIRES, OR CAUSE FIRES!
The connector is at the lower left of the steering wheel assembly. To remove plastic cover the wheel needs to be telescoped to max and the 3 screws removed, two hiding behind a straight-ahead steering wheel. The two halves are snapped together.
This works on my car (98 GS400 with no DLR lights) and should work on cars with DLR (Canadian, US 99+). Also works with all the combinations of switching states (auto off, auto on, flash etc. etc.) Fogs stay on with HIGH or low headlights, and off as before with parking lights. Great for twisty/hilly roads and country lanes. Not much use for straight highway driving.
B: Fogs with High Low AND Parking - NOT tested
To keep the fog lights on with the parking lights (and high and low beam) try this variation:
• On the light switch connect the –ve end of a diode (1amp / 50V or similar) between pin 11 (or 18, as they are looped) and the +ve end to pin 15
(18 grounds with low beam only, 15 grounds with parking lights, 11 is fog control (via light ECU)
BEWARE I haven’t tried B so be careful. Can someone with experience of car electrics verify that this works? I wouldn’t normally post something I haven’t tried but this seems a lot easier. I do not know how much in common other years and models have for light switches but assume that it is a lot.[B]
Both these methods still use the auto lights off function to avoid flat batteries.
There are easier ways. I've never had the time to photo and document the method in detail, but perhaps you can? This took about 20 minutes.
Here's two old posts I made:
A: Fogs with High and Low beams - Tested
Sorry no pictures and not too many specifics but this works:
Connect a 1 Amp diode between pin 14 (Red with Black strip) and pin 11 (Green with Black stripe) on the headlamp switch connector, with the + end of the diode connected to pin 14.
This grounds the fog relay when the headlight relay is grounded. To protect from installation mistakes put a 1 amp fuse (optional) in series with the diode. Power comes to the existing 15A fog fuse directly from a 120A fuseable link so no fear of overload.
BEWARE; MISTAKES CAN MELT WIRES, OR CAUSE FIRES!
The connector is at the lower left of the steering wheel assembly. To remove plastic cover the wheel needs to be telescoped to max and the 3 screws removed, two hiding behind a straight-ahead steering wheel. The two halves are snapped together.
This works on my car (98 GS400 with no DLR lights) and should work on cars with DLR (Canadian, US 99+). Also works with all the combinations of switching states (auto off, auto on, flash etc. etc.) Fogs stay on with HIGH or low headlights, and off as before with parking lights. Great for twisty/hilly roads and country lanes. Not much use for straight highway driving.
B: Fogs with High Low AND Parking - NOT tested
To keep the fog lights on with the parking lights (and high and low beam) try this variation:
• On the light switch connect the –ve end of a diode (1amp / 50V or similar) between pin 11 (or 18, as they are looped) and the +ve end to pin 15
(18 grounds with low beam only, 15 grounds with parking lights, 11 is fog control (via light ECU)
BEWARE I haven’t tried B so be careful. Can someone with experience of car electrics verify that this works? I wouldn’t normally post something I haven’t tried but this seems a lot easier. I do not know how much in common other years and models have for light switches but assume that it is a lot.[B]
Both these methods still use the auto lights off function to avoid flat batteries.
04-11-03, 04:08 PM
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>A: Fogs with High and Low beams - Tested
>B: Fogs with High Low AND Parking - NOT tested
my set up is fog light with the foglight switch, no need for low beam, or parking light
>Both these methods still use the auto lights off function to avoid flat batteries.
-same here, as soon as you turn off the engine, the fog goes off.
also, I don;t think your method will work with DRL model, the DRL ECU control the fog light which cut the switch and the relay. I think your method would force the fog light to comes on with the low beam and even bypass the fog light switch (ie similar to shorting the low beam with the fog at the light, correct?)
my goal was to use the fog light switch and allow you to turn on/off just the fog anytime the car is running or anytime if you decide to do so.
but your method also show another way to do this, and definitely simpler
>B: Fogs with High Low AND Parking - NOT tested
my set up is fog light with the foglight switch, no need for low beam, or parking light
>Both these methods still use the auto lights off function to avoid flat batteries.
-same here, as soon as you turn off the engine, the fog goes off.
also, I don;t think your method will work with DRL model, the DRL ECU control the fog light which cut the switch and the relay. I think your method would force the fog light to comes on with the low beam and even bypass the fog light switch (ie similar to shorting the low beam with the fog at the light, correct?)
my goal was to use the fog light switch and allow you to turn on/off just the fog anytime the car is running or anytime if you decide to do so.
but your method also show another way to do this, and definitely simpler
Last edited by BananaGS; 04-11-03 at 04:09 PM.
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