Thanks Sailor I needed your input for myself....I did a few more checks yesterday.Gives me a little more to think about re:the brake switch.
But I did disconnect mine, which is same as using it as we know. Did not act like the OP's symptoms BUT....my bike doesn't have any electrical problems so of course can only try to duplicate without breaking anything. And clear faults later.
I disconnected the brake switch then turned on the ignition, then brake light comes on but the General warning light still goes off after a few seconds and the ABS warning light stays on the fast flash as per your description. But will show a fault with the GS911, that I know for sure done that before. So one fault I'll read/clear later.
Turn on the ignition then disconnect the brake switch and the brake light comes on but also as they should the servo-motors.One more fault to be cleared off....
Only way to keep the warning light on at all time with the brake switch disconnected is to remove the ABS relay but the switch does not have to be disconnected to do that. And with the relay removed, the ABS light(left) doesn't function anymore.Relay fault showing??? Don't know yet and don't think so but certainly a switch fault.
Where it gets tricky is the relay diagnostics as it is a two contacts relay, as it flashes it alternates bewtwen contacts on/off and at rest "no power/ignition" it is in the closed position/contact on. And described somewhere else I have seen as a "No contact" relay, that's a little misleading that description. Still beats the other description....
Then with bike underway and self tests completed is looks like it is always powered and the contacts are in the open position but there is still an internal contact in that relay.That's how mine was acting up, the extra heat from the "power on/dirty contacts" seemed to affect its function and then it worked again when it cooled off after a period that was getting longer and longer.But no faults there on the GS-911.
Depending on which contact is bad in the relay that is if
there is a bad one, it could affect the general warning light function but the ABS light(left) wouldn't function as it should. And from my own recent experience....NO self test/bad relay doesn't show fault codes on the GS-911.
So...I'd also like to know if the OP's ABS light(left) is acting normally....fast flash at first then slower and goes off after the rolling self test.
Disconnecting any of the switches or ABS sensors always give me faults on the GS-911, either a switch fault or sensor fault.Would act the same with a broken wire/non functioning switch. And the OP hasn't found any of that.
I was wrong on the Flasher Unit controlling the flashing lights in the dash but took the stethoscope to figure that one. Can't trust my old ears anymore....
So the BMW schematics are probably right and so is Clymer at least on that one.A little busy no time to get back to that but will eventually.
But so far...ABS relay controls the flashing of the ABS light(left) only. Flashing of the General Warning light is controlled I'd assume by the ABS brain, may even be a relay in there??? I can get the "general warning" to flash with ABS relay disconnected and the brake fluid level sensor also disconnected. And of course the "Flasher unit" also disconnected to take that one completely out of the circuit. So something in the brain is flashing the "General Warning Light".To some extent the two lights work together but from within the brain....
I'll try to go back to that this morning with the writing pad/camera this time.
What could help the OP more with the diagnostics is voltage checks at the connector/bulb and some continuity checks with the Ohmeter to indentify a possibly broken wire/bad connection.Some of that may be hard to do considering the wires going into the ABS brain aren't too accessible unless the ABS is disconnected.
I am reading 0.06V at the brake light wire with ignition ON....normal I think as it is how they check the integrity of the brake light circuit/bulb by sending a low voltage through the circuit.
Bad connection somewhere may equal to more resistance on the circuit....and then the brain think it is a fault and....Warning light on and both bulb filaments on.
And certainly hard to diagnose as all them functions/lights etc. act differently depending on engine running or not and as far as I can see....completed self tests including the rolling one.
And from pulling connectors etc....could there be two faults masquerading as one or a bad connection somewhere?....first thing I'd do anyway is clean/check all
the contacts at all
them connectors.....easy things first.
Now....if all the diagnostics/repairs prove unsuccessful, there may be a way to tap into the brake switch wire going to the ABS brain and keep the normal servo functions operating. Involves a relay to reverse the function and some rewiring of the brake light circuit to take it out of the "brake light check" loop. Not sure yet, I was going to wire such a setup and throw it under the seat in case I loose the servos/abs and have to de-ABS my bike roadside and avoid going back home on the residual braking function and no brake light.The plumbing part is easy and then a little roadside temporary wiring....Easy(ish) to do with the ABS disconnected but not sure yet how that could work with a functioning/connected ABS system.I may try that as an experiment.