2008 scion xb fog wire/relay info

Hi,
I would like to rewire my factory fog lights to act as DRL's and come on when the key is in the "on" position. I would also like to use most if not all of the existing parts and not have to purchase additional kits from a 3rd party. I cannot find any wiring or relay information for the lighting system for this model. If anyone has information to assist in this endeavor I would appreciate it.

Thanks in advance

Test the switch, see if it has an input wire that goes to 12 volts when lights are turned on. Cut and join to ignition. You may find that an underhood relay might need the same treatment but it's easier to check at the switch. You might have a legality problem though.

Thanks for the response but I tried that and I am blowing fuses trying to decipher what I have. I think the fog system is a positive ground circuit. The only time the system goes hot is when the lights are in the on position, I need to change that. I also do not know where the relay is or what colored wiring I need to look for or where the wires are routed. I have scoured the net and found many of the wiring color code text descriptions but they never mention anything about the OEM fogs or the detail that I need. I found a fog light installation PDF file but all Xb vehicles are factory prewired and all you need to do is add the lights and switch, a lot of help that did for me ;)

I am really hoping that someone has done a mod like this before and can lend a quick tip or has access to some detail I need.

a "positive ground circuit"? the suspect wire may rest at ground and need to be activated like the trunk release on a Camry using a relay. how are you testing the wire?

I am checking the circuit with a voltmeter. I thought it was an easy swap until I started blowing fuses attempting to swap wires.

The fog light switch connector has 4 inputs:
Green
Green
White
Gray

The center green and white wires are for the illumination for the switch and are hot for parking and all headlight functions.
The remaining green wire goes hot only when the headlights are on low beam. I had cut this green wire and attached other wires to it but blew fuses. I later found out that when the green wire is grounded the fogs illuminate as they should. Sorry if I do not know the correct terminology for the circuit, but when the positive voltage wire is grounded the fog relay actuates and the lamps lite.

So .... I need to find the relay or a wire bundle close to it so I can properly remove the headlight circuit and use a key circuit in it's place to actuate the fog relay.

use ignition power to a relay to convert the polarity to negative and use that to trigger the wire to turn on your fog lights.

ckeeler wrote:

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use ignition power to a relay to convert the polarity to negative and use that to trigger the wire to turn on your fog lights.

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Hi,
There is a problem with that.

Problem:
Right now I only have access to the switch. I would need to ground the green wire to get the fog relay to actuate. The green wire is only hot when the headlights are on low beam. This is how the switch works in it's present state. I want operation during key "on", which there is no power to the switch at the moment, only on low beam headlight mode.

I see where you are going with your idea but I need access to the circuit before and after they get to the relay or the relay itself. That is my dilemma ...... the only solution I can see is to get closer to the relay or circuit wiring but I need more precise info, it's VERY cramped under the dash and there are many similarly coded/colored wires.

I do appreciate the comments, please keep them coming

Take that green wire, cut it input side to 87a, switch side to 30, ground to 87 and 85, ignition live to 86, job done. second option:- go to fog light power feeds under hood, cut + side, feed to 30 on relay, 85 to ground, 86 to ignition source and 87 to battery via a 15amp fuse, 87a not used.