The R1200GS Canbus system is somewhat reluctant to be messed with. OK, that is an understatement. It wont tolerate being messed with.
So, if you want to add accessories, you need to either wire them directly to the battery, or create a fuse box. Of course for the fuse box to work right, and to prevent your accessories from killing the fairly small battery on the 12GS, you need to hook the fuse box up to a relay.
Here is the wiring diagram I made up, and used. Note that I have the GPS wired directly to the battery still, since I want power at all times. If you have a unit with a battery, you can use the fuse box.
Lots of wires can be messy, but BMW was thinking about us when they elected to furnish a tool kit with no tools in it (for all intents and purposes), so I put the fuse box in the spot where the tools used to be. It is the perfect location.
I used a Blue Seas fuse box because it is a quality unit, and marine rated for protection, so I figured it would work on a bike. I got it for $20 on E-bay new.
The relays are under the fuse box, and it is held in place by the tool strap. This makes it easy to lift up if you want to add more accessories, or change a fuse.
The big picture. Pretty clean considering I did it in 25 degree temps, outside, at night. When I add more lights I will make the wires a little neater, but it works.
I took the signal power for the main 30amp relay, purchased at Pep Boys for $3.99, from the testing plug at the back of the fuse box. I used the green wire with blue stripes because it is ignition on only, so the fuse block is only powered when the key is on. The power needed is so low that the Canbus ignores it.
When I wired up the fuse box, I also installed some new Motolights that I got for a steal at just $250. They work well, though I may add more light, as you can never have too much.
The big picture.
The wires coming up the brake lines are nearly unnoticable.
I put the switch on the inside of the left brush guard, which lets me turn them on and off with my index finger, bit is out of the way.
Anyhow, it works great. I did 200 miles today and no problems. After dark the Motolights definitely improved on the already good stock lighting.
I also routed the power for my electrics to the fuse box, and have set it up to add my new FIAM horn as soon as I find a 5amp relay.
Finally got the rest of the lights installed on my GS. Hey, it was too nasty to ride.
So, my total number of lights is back up to my comfort level of 5! Seems this is where I always end up.
I now have a new set of Motolights, $250 new off the IBMWR web site, and a set of Hella FF50's $40 from E-bay, and a Bestrest adjustable light bar, that I got from ADVRider for about $100.
Anyhow, here is the finished product (cept I need to fab a light switch mount for the Hellas.).
Hella FF50 mounted.
From below.
All lights mounted.
Low beam only, actually it isn't that bad alone.
Low beam with Motolights. My normal daytime running condition.
All except the high beam. I was using a flash to minimize glare so you could see the lights better.
All lights, no flash, from Motolight level at about 8'.
All lights, including high beam, at the Hella Lights level, no flash.
I think these will be great for my favorite night time twisty rides, and long straight two lane blasts.