SSBrian

I have a 2008 Mustang with the factory HID head lights and the Pony Package fog lights. I will be changing the fog light bulbs to LED and they will be Daytime Running Lights also. I plan on adding a relay, diode and switch (A switch to turn off DRL). The diode is to prevent back feed to the PCM, like the the factory did for to the fuel pump relay. Just running it by the forum to see if my thinking is right. Also what brand and model H11 LED do you find to be the best?

07 Boss

Maybe I'm simple but could you not just run a switch to the fog lamp relay?

SSBrian

The the fog lights will not be automatically turned on with the ignition on (Engine Running). That would be the same as turning on the fog light switch on the dash, except it could be left on when you walk away from the car.

07 Boss

Oh, I didn't look carefully at the schematic. I thought the cut off switch was the trigger for the relay.

Here's a couple of thoughts though. I ran my electric water pump from the cruise control circuit which is hot only with the engine on. That seemed like the easiest way when I was trying to figure out an engine running power source. Also, can't you activate the factory drl system and piggy back off of that? That is just guessing as I'm not sure how that is wired up or if that's even possible to separate the drl signal from the headlights as I think I remember it being the headlights with half power and not a separate circuit. Anyways, sorry I couldn't be more help, I'm a simpleton when it comes to wiring.