R90 wiring extra brake lights

[plehman]

Having a lot of fun renovating an old set of Wixom bags for the R90/6 1976. The original lights were missing the lens and were corroded and nasty. I bought some simple Truck lights - which fit exactly, screw holes and all. Two bulbs, a single black wire, ready to go.

So what's a clever way to tap into the brake light circuit?
Do you think the four small bulbs pulling current from the brake will effect the brake main light?
Probably should add a fuse?

I admit to being an electrical neophyte. No explanation too simple.

thanks!

[1074]

You shouldn,t have any charging issues, as long as your charging system is working properly. That said, the most commonly found wiring is running the wires from the bags into the taillight and hooking them up to the brake light terminal on nte back of the taillight reflector.

[20774]

Not sure how it was done on my /7 which came to me with the Wixom bag lights operating when I step on the brake. They're not running lights, though, only added brake lights. They were probably done as Bruce suggests.

[plehman]

So you just tap into the rear brake light terminal? (numb 8) I guess best is to solder it.

Do you need to add a ground? There isn't one on the light, but was one on the original system.

Sorry to be so basic.

[20774]

That diagram doesn't have enough detail. On Snowbum's page, he has a diagram that includes the R90/6:

http://bmwmotorcycletech.info/schematic1975,1976.htm

It appears that the brake lights are connected into pin 54 while pin 31 is ground. On my Wixom bags, the ground is inside the bag where the spring clips connnect the bag to the mounting frame. My ground wire has a terminal which is connected to one of the rivets that holds this together. You can use a digital ohmeter to identify what part of the internal frame is connected to the bike's chassis ground.