I finally got to a shop to buy wire taps.
so here is how you get it done - you get out your light switch and you tap together 'A2 - automatic light yellow/red' wire with 'A5 fog light yellow/white' wire.
now when you put light selector into 'home' position your front fogs will light up when engine is working. 'home' function also works as usual when you shut down engine and fogs turn off in 30sec after you exit the car.

works fine.

 

do you know the difference between the 997.1, and the 997.2 headlight switch? do you have access to the wiring diagram for the 997.2 like you got for the 997.1? i have been trying to have that function and bought the dectane module but i have a trickle charger on the car so that is not a good solution. i am not familiar with the home setting , what all does that do, just delay the lights shutting off for 30 sec? any help will be appreciated. could you run a hot wire from the ignition switch to the fogs? but then you could not turn them off with the car running. mike

 

you would need to find a diagram. then take voltmeter and check - when switch is not engaged both wires should have logical '1' which will be somewhat close to 11v.
when engaged it will be ground. 'home' wire goes directly to ground, fog light is more complicated - it gets to ground via relay driven by switchable power but works fine when connected directly to ground in my car too.

some signal wires have 0v and are engaged by logical '1' - so you need to make sure it is same. 997.2 has different engine ECU, i am not sure what it has for front ECU. may be same, may be not. to know for sure you need to find its wiring diagram.

'home' function is an odd thing - when you drive into garage and turn off motor it lights up fog lights so you (apparently) can see around in the garage, then in 30sec car turns fog lights off.

 

Very cool. So for times that you want less bling, you could turn the lights from 'home' to the 'off' position?

 

What happens when you switch the lights to the "on" possition?
Does eevrything else work as normal?


Good find -

 

yes, as there is nothing done.

and yes, in 'off' position it is all off. all you do with this hack is to connect fog light signal to a ground like it does when you turn it on in a normal way. but this way other lights (side, rear) do not engage. just fogs.

 

Depending on where the readers/owners are, wiring the fogs to be always on when the engine is on (ie running fog lights when there is no dense fog) is likely a traffic code violation. I know it is in Germany and likely the EU. Not sure of the US. Generally a bad idea as its just a hair less annoying than running with high-beams on all the time. Foglights are not driving lights.

 

Well, aren't the LED fogs the DRLs on 997.2s?

 

It's not illegal any where in the US I am aware of and I'm an ex-cop. No different than running with your headlights on.

 

You guys are not reading - fogs are turned by switch when it goes into 'home' position. In original 'off' position all lights are off.

With default fogs light switch position you first turn on side lights, then if you pull out switch it turns on fogs. With this hack I did you can turn on fog lights only, with side lights remaining off.

 

As of 997.2 question I looked at a catalog I have and it seems light switch part number is same. Get it out (press switch in and turn it a bit to lock then pull out) and compare color of wires on A2 and A5 pins.

 

Nice! Thanks utkinpol! Will be doing this asap.

 

this is to use fog lights as DRL? We have headlights always ON as DRL here in Canada with no option to turn it off thru PCM, will this mod turn headlights off??

 

to turn headbeams off you need to find mechanic with piwis and reprogram ecu.

 

Thanks for the info. I'm going to get this done to my 997.1. I have ROTtech DRL's on my car, and I would love to have the head lights off, and have the fogs always on when I start the car.

Since I'm not a mechanic, I have someone who can get this done for me so I don't mess something up!!