Thanks for the reply Ideally I wanted to keep the fogs enabled but not wanting to run resistors I think I will disable the fogs and install a set of these, then code up to set fogs as DRL's. If you put 12v on pin 1 they are dimmed so they must be controlled by the board inside the lamp units (no PWM signal needed? So it sounds like it would basically need a 12v supply running to this pin when headlamps are on, I would like to have the CECM control this but not managed to find much info to help with that.
With the two brightness levels they are designed to work as follows?.. DRL = full brightness, Headlights = dimmed, Fog = full brightness
Sorry for the late reply to this, been mega busy recently. I don't have resistors on mine as they got stupidly hot when running so I wasn't comfortable with it, I do have a bulb out light on the dash because I'm not running resistors, bit of a trade off I suppose, still looking for a work around for this.
You can leave the fogs enabled and code fogs as DRLs, remember to use USA style with fogs as DRL, took me a while to realise they didn't turn on until you release the handbrake
The DRLs will be on when the headlights are not on, as soon as you turn the headlights on then the DRLs shut off. If you have headlights on and want fogs, just use the switch as usual and it will switch everything on. I've installed a 30byte CECM too so I have fogs as cornering lights coded which shuts one DRL off when turning at certain speeds
Brightness how I have them is 100% DRL, off with headlights, 100% fog. You can code different brightness but I didn't really see any difference and was a little concerned it may change the fog brightness and I want that at 100%. How you describe is how they are meant to work though I believe.