I wanted to mod my 2001 Tundra to have its FOG Light be on with any Beam and I couldn't find any info so I figured it out myself. I think Yota had many changes with the light wiring so the diagrams that I found were not what my 01 had.
This will allow you to have your factory Fog Lights stay ON with Any Beam (and parking)... Its not the anytime light fix; as I dont want them on without my lights; and my model does not have DRLs.

The simple solution is to remove the dash fog switch and cut the Red-Yellow wire; just long enough from the connector that you can join it to the Green wire. This allows the parking lights to switch the relay on for the fogs; so they will stay on with the High and Low beams in use; and will turn off with the lights off of course.

Fog Dash Switch:
Green - parking lights hot
white / green - dash lights ground/dimmer
green / red - to fog relay (this switches the relay on)
red / yellow - low beam (when pushed on; the dash switch connects to green/red to switch on fog relay; when high beam comes on the red/yellow goes off)

Fog Relay:
green / red - from dash fog switch (this triggers the relay on)
pink - hot to fog lights
white / black - ground
blue / red - hot from fog fuse


this is really easy to do just b/c the dash light is wired for a bulb which gives you that hot wire to tap into for the relay.
Hope this helps someone.
-Doug

 

Seems legit.