SloopJohnB@mac.com

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tester123

I did think about this in past and came up with couple ideas:

1) Place LEDs directly inside the Front Fog lamps and turn it on (find hot wire) with ignition.
2) The more extreme but could look nice is to dismantle the Audi "rings" chrome logo and with equal spacing, drill tiny holes inside the rings and place surface mount LEDs with some epoxy, wire them to hot wire. -just never had time to do it.

EODphillips

I have been thinking of doing this too, where would I find a ignition on connection under the hood? I'd like for the leds to turn on with the ignition on and off with it off. Pretty simple I would think but I have been searching the forums all afternoon and it seems no one has done it. Fog lights on has been all I could find.

Airbag

I'm not into the bling but I do have to do something with the foglights.

EODphillips

So does anyone know of a good connection to pull power from with the ignition on? I would like to run it from under the hood so i don't have to go through the fire wall. I don't want to have to turn a switch to turn it on, just looking for a simple positive power connection, with the ignition on.

Airbag

Hmmm not sure.
What is your plan and what current do you plan on drawing? Are you going to use that signal to flip a relay to provide fused power right from the battery ?

That's what I would do. If that is the case just about any switch power would do.

If you plan on using this line to power your lights directly, then power consumption ie current draw may be an issue. Personally i would piggy back in to a relay off the fog lights, then you can have switchable control.

EODphillips

My plan is to run DRL LEDs, I would really perfer not to have to hit a switch or do anything to turn them on, just start the car and have them on. All I need is a positive power source that is on with ignition, the ground is easy. I would think this would be easy but its looking increasingly difficult. I could just throw a simple switch to turn them on or jump off the fog lights but I would like to do the hard work now and be lazy from now on and always have them turn on automatically.

Airbag

I understand what you're saying but you still need to know what draw your led cluster will be so you don't overload the circuit of whatever you tap. What you want to do is really easy.

I'm sure there would be a switchable 12v somewhere you could tap off of for a relay. Anyone with a schematic that could help

tester123

You want simple, here it is: Take one of those 12v test probes and start probing around fuse box. Find one that's hot WITH ignition turned on. Pull that fuse and check which side is hot. You want to tap the side that is NOT HOT. Why? Because the fuse is there to protect -should you over load it. As a safety precaution, I'd suggest you run a 500milliamp or 1Amp in-line fuse in your wiring. LEDs shouldn't draw that much current anyway so, you'd be alright. The in-line fuse is a safety net so that a short in your project won't propagate all the way to fuse box's fuse.

Now, if you are toying with high power "cree" LEDs or similar (they get Very Hot! so, you have to plan for that), you really should include a small 12v (~10+amp contact rating) relay and draw actual power to LEDs from the battery (again, another fuse here). Still, I suggest the inline fuse to the relay from fuse box. In other words, the "HOT" wire (with ignition on) will drive the relay which in turn switches power from battery to LEDs.

Dress the wires neatly and secure them.

That's it.

GTA_Driver

There is a DIY guide somewhere on running your fog lights as DRLs (for US models, since Canadian models already run fogs as DRLs). Tap your LEDs to the same source as doing the fogs, and you're done.