I have found many topics regarding rewiring the foglights in 90-94, but not any for 2nd gen owners. I have successfully done it, but I recommend this ONLY to technically proficient people that have knowledge of automotive electrical and Bosch-style relays..

Goal: Rewire the fog lights so that the factory switch controls them, but they can turn on independently of the headlights. They can be wired to turn off automatically with the ignition or the parking lights, or be completely independent.

1. Loosen the underpanel on the driver's side of the dash using the two philips screws. Disconnect wiring that is attached and remove the panel completely.

2. Remove the ignition key switch bezel by prying it off carefully -- it is pressure fit.

3. Remove the trim panel that would be in front of the driver's shins.... it takes four 10mm bolts and one phillips screw.

4. You should now be able to see the fusebox. It has to be partially removed. Make sure the car is off and unplug the five electrical connectors that are plugged into the fusebox above the fuses. Remove the two 10mm bolts and the single 10mm nut that holds the fusebox in and pull it down from underneath the dash as far as you can.

5. The fog light relay is on the backside of the fusebox. It is the small black box that is located nearest to where the leftmost fusebox bolt was positioned. (Turn on the headlights, then the foglights, you can feel the relay click as the fogs go on and off) Remove the relay using a small flat-tipped screwdriver to release the catch on the right side. (easier said than done)

6. I used four different colored wires that were about 8" in length, with a male spade at one end and a female spade at the other to relocate the relay. This will let you modify the wiring without having to modify your car's OEM harness. Since the relay can only go in one way, it is easy to plug the four extensions into the relay receptacle and then onto the relay. Test your foglights at this point to make sure they are still working correctly.
Here are the colors I used:
Blue: Ground Signal From Fog Light Switch to Relay (- Trigger)
Green: Positive +12V Signal from Headlight Switch (+ Trigger)
Yellow: Constant 12V From the Fog Light Fuse in the Fuse Box (+ Source)
Red: Output from Relay to Fog Lights (+ Output)

7. Replace the fusebox, bolts, nut and plugs.

8. Depending on how you want your fogs to work, uise a voltmeter to locate one of the following wires (it will draw next to no current to open the relay, so even small wires are OK):
Ignition Control: wire that is hot with ignition on, but not with ignition off
Parking Light Control: wire that is hot with parking lights, but not with lights off
Independent: wire that is hot all of the time

9. Cut the green wire from your new relay wiring bundle and reconnect it so that it goes from your relay to the wire that you just found. (cap off the green wire from the fusebox so it will not ever ground out) Now test to make sure everything works.

10. Replace the lower dash panel, underpanel and ignition switch bezel.

That should be it! I did this last week, so I hope I didn't forget anything!

 

nice post!
im going to go and do this with mine now

 

Only applies to the 1995+ LS400, the 1990-94 will be different.

Darren

 

yup. still want to do it though! haha

 

Do you know if it will work for the 98+?!!

Please say yes... please say yes.....

 

Here's what I did put fogs into corner lights and made the orignal fogs a DLR's

 

How exactly did you put fog lights into your corner lights? Do you have a photo that show it better?

Darren

 

I used a dremmel tool to enlarge the hole in the corner light.
Sorry ,it seems since the site updates they have lost most of my pics from my gallery.
As for the orginal fogs I ran new wires to the fuse box and used the fuse for the heated seats . It was there even thought my car does not have heated seats.

 

Here's an old pic:

https://www.clublexus.com/gallery/sh...cat/all/page/1

 

I see, I will probably do something about the corner lights... that little peanut bulb is pathetic looking. Gotta think about it a little, though.

I imagine that the 98 would have a very similar wiring system, but wouldn't know unless I started taking one apart. Does your 98 have the fog light switch on the stalk like the 95? It would be a rotating swtich just inside of the headlight switch. If it is there then I bet the rest of the article will apply as well.

Darren

 

Nice

Curiously, do you get any warning lights on the dash indicating a burned out bulb or such?

 

No -- and you shouldn't. The system will see the lights exactly as it did before, I only altered the trigger mechanism. Do you have a 95-97 and did you follow the instructions that I listed above? If so, the only idea I have is that the wire you tapped into for the positive trigger was somehow a voltage-sensing system for the headlights.

Darren

 

Haven't done it to my '97. I did do something similar to another Toyota and it saw the mod differently so got a light on the dash indicating a bulb failure. Only came on when I applied the brakes so I wound up with in inside brake indicator light so I just left it.

 

Did exactly as discribed, but I lost control of the fog lights via stalk. And the fogs will not operate when the HID's are on. They either work with the Parking lights, when everything is off or Nothing.

 

Bummer

They must have changed things slightly for your year. You know what that means...dump the UCF21 for the 20...then the mod will work. (I haven't messed with mine so I can't verify.)