I'm converting my fog lights to LEDs to act as DRL's on my 2009 CLS63.
Can anyone give instructions on how to rewire them so that they automatically come on when the car is started without having to manually turn them on with the fog light switch?

TIA

i want to do this as well... i thought there was a way to do it with STAR but i'm not sure...

Simple question: do you use headlight always turned on when starting your car (option available in computer menu) ?
This is what I'm doing and I linked my LED with city light wires so very easy to get LED in addition with headlight

If you plan to use LED light only, the solution would be to get power directly from your alternator (dynamo)

Hope it helps

Yes, this is correct. You can wire the positive wire directly to the back of the alternator. Lights will come on as soon as you start the car. Once this is done you will get a pesky message about your fog lights every time you turn on your headlights. Small price to pay for a sweet look

I don't use that scenario (from alternator) so I cannot confirm for the pesky message on the dashboard...

But I confirm using the LED connected to city lights and lights turned on as of ignition on (option exisits on menu) has no impact and display no dashboard message

Cool! So feeding wire to the city light wiring has no impact or voltage issues?

I would use one of the city lights to flip a relay, then run a new, fused line to the battery or high current source to drive both sides.

Yep ! You can give it a try and check by yourself.
It's very easy and quick to wire and check before definitely leading the wires to the front bumper.

I'm based in Europe (France) but don't see any reason why it shouldn't be the same for you guys overseas

BTW, this is LED and very low consumption.