Thanks - and having diodes to hand I can now save you some time....
Boxster 987.2 2009 Non-Xenon :
- Switched off "DRL" (which is actually just dipped beams and tail lights in non-xenon cars) in the on board computer
- Using a wiring diagram (from a Cayman, but hoping and subsequently proving it's largely the same) , tried the hack, but between the yellow/red and grey wires. The grey wire is the sidelight/position light circuit.
- LED sidelight bars and tail lights illuminate with the switch in the "Home" position, BUT the "lights on" warning sounds when the key is removed - correct behaviour for the sidelights but not the desired effect. I guess the foglights aren't connected to the warning beeper as they go off when the headlights are turned off in any case (normally), which is probably one reason why the hack works......
- Reverted to the "standard" hack as described earlier in this thread which works fine
Ho hum, now off to buy some LED fog bulbs of the lowest output/least focussed beam pattern I can find.....! 😉