I am installing an Innovative Motorsports Air Fuel Mixture gauge and I need a ground and a switched positive under the dash. They suggest not using an ignition ground to avoid a "noisy" source. Anyone got any suggestions?
Br/W off ignition switch is switched positive with the key. Nice wire to work with. If you want to run a high current application like a light or grip heater, send this to a new automotive relay and large positive fused wire from battery. This is very clean. Battery ground. I used this wire and relay to power a GPS. Did not really need the relay but thought I might add lights later. Head light wire may run a/c as well as 12v d/c and not be "clean" enough. This is from a 2010TE schematic. The Br/W goes to all the relays. I could not find a 2011 511 schematc. BMW might have changed the colors.
Suputin, I've been studying to make my post more helpful. There are apparently 6 wires coming from the ignition switch. The 2011 schematic only shows two. The Y-R is hot from the battery. The Y-Sb is switched positive to the RH starter switch. This should work for your purposes especially if you use a relay. One of the other wires may work and maybe even better but I just can't find any more info for you. Let us know how you wire it. Good luck.
I ended up using the circuit that runs the headlight running light because it was easy to access and tap into. For ground I went to the steering stop bolt on the frame because it was close by and easily accessible.
