1975 R75/6 Front Brake Switch Question

[brook.reams]

Folks,

I'm trying to identify the correct front brake switch. It looks like I have newer /6 version of the throttle housing, not the older /5 version, which is part # 32721233537 HOUSING RIGHT

In looking at the Max BMW Part's Fiche, it shows the clutch switch as the same part for both the clutch and brake switches on the handle bar.

Can someone confirm that the clutch switch is also used as the front brake light switch?

Thanks for you help.

[schrader7032]

Look at this figure from RealOEM:

http://www.realoem.com/bmw/showparts.do ... g=61&fg=25

This shows part number 61 31 1 243 403 on both sides of the handlebar, supposedly one for clutch and one for brake. Interesting, though, the table only indicates a quantity of one for the bike. But given the way the switch works, I would think the same part will work on both sides. You pull the lever and the microswitch is activated. Both clutch and brake use the same type of lever.

[brook.reams]

Folks,

Well, I found the answer to my question after digging around on the bike a bit more. This model has the master cylinder mounted on the spine tube under the gas tank. The filler cap for the brake fluid has 3 wires connected to a float connected to the low fluid warning light. That's all I could see at first.

HOWEVER ... as I looked more closely at the master cylinder, I suddenly noticed a second switch at the back with two wires which isn't very visible. This is the front brake light switch and the two wires rout into the wiring harness. It looks like a cylindrical switch, and is called out in the parts fiche for the "Brakes" section as:

61 31 1 244 334 STOP LIGHT SWITCH

Funny how sometimes you can't see what's right in front of you !!!

There is also a stop light switch shown on the "Electrical" section of the fiche, and is the one that originally caught my attention.
61 31 1 351 662 STOP LIGHT SWITCH

I believe this one is the older /5 handlebar mounted cylinder switch.

I also noticed what Kurt pointed out in the electrical section where it shows the clutch switch duplicated next to the left side switch assembly. I too thought that was the front brake light switch, and you just used the same one as the neutral switch. But, there aren't enough free connections in the headlight shell to attach those leads, and that got me scratching my head over this.

Onward, and thanks for the input Kurt ...

[f11at125]

Is it safe to test the "brake failure" light by connecting those two tabs on top of the brake cylinder? My light never comes on at engine start; the Harley guy at what serves as my shop for non-BMW parts said he thought that was normal on R75's, but I can't imagine it is, or? The light is functional (I swapped it back and forth between GEN and BRAKE FAILURE and it lit in GEN's socket). I'm not sure if i'm trouble shooting a feature, not a flaw - anyone?

[schrader7032]

The switch or float inside the M/C cap just drops down and makes contact somehow. All it is doing is creating a continuous path to ground. You should be able to momentarily touch them. Why not just actuate the float in the cap?