Originally Posted by cobbler
Then there are two little silver head screws on the inside that must come out because they hold the cover on to all the guts. One you can see on the top right and the other in underneath a silver sticker, yes under a sticker.
Oh Cobbler, on all counts you were right on the money!
With everyone's help (and that of a fellow rider), in two hours, we disassembled, diagnosed, and fixed the balky 1999 BMW K1200RS left turn signal switch!
As you noted, there were a few "mysteries" to be solved:
- The first mystery was to locate second of two #6 torx screws on the inside of the turn signal combination switch left assembly. Just like you said, it was in the middle of the sticker; I just removed the sticker instead of punching a hole in it. In the beginning, I didn't have a #6 torx screwdriver (that's really really tiny for a motorcycle) so I used a 1mm allen wrench. Putting it back, I bought a set of really really tiny torx screwdrivers.
- The second mystery was how to remove the orange paddle on the outside of the turn signal switch assembly. Turns out you destroy the black tie wrap and remove a small plastic bulkhead panel, and only then does the end of the orange turn switch paddle come out.
- The third mystery was how to disassemble the half-inch tall half-inch wide switch cylinder; the trick here was brute force, gently but firmly applied. I worried that I would never get it back together; but, it turns out, you can take it apart and put it back together but the top of the cylinder is directional so mark the white plastic before you take the switch cylinder apart.
- The fourth mystery was how the damn thing worked! It turns out that the 1999 BMW K1200RS turn-signal switch is an always-on contraption. Yup. The two metal contacts are always in contact except when you momentarily depress the orange paddle, which presses on the white cylinder, which pushes down a paper thin 1mm sliver of plastic in between the two brass contacts, separating them, and causing the turn signal to activate.
- The fifth mystery was a diagnosis of the problem. It turned out there was a tiny aphid-sized lump of black goo on the tiny 1mm wide by 1mm tall paper-thin plastic sliver. The black goo was keeping the contacts open, not allowing them ever to close, so they were always in the "cancel" mode. Wierd! I never would have guessed this had I not seen it with my own eyes, that black lump was smaller than the size of a pin head.
- The last mystery was how to put it all back together! It took a few tries (the head of the cylinder itself is directional for example, so you have a 50% chance of getting it right unless you mark it beforehand - I recommend you do 'cuz the more you manhandle it the more chance you have of breaking it). My mistake; your gain.
- In order to put it back together, I had to remove the third #2 philips bolt on the underside of the switch assembly. You really don't need to remove it until the end (go figure) when you try to reassemble the tie wrap and black plastic wire separator which holds one end of the orange paddle in place - but again - my mistake is your gain. You may as well remove that third #2 Philips bolt at the beginning.
Hopefully I'll have time to post some good pics so the next guy has the benefit of Cobbler's knowledge!
See also wiring diagrams
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