Rear brake light problem

[markwin]

Several years ago I did the Absectomy all went well after a few issued resolved and everything worked as expected.
Fast forward to today and now the rear Brake light initially works when pressing rear brake pedal but on subsequent use it stays unlit.
The front brake lever can illuminate the brake light each time every time but brake pedal will only illuminate when ignition first turned on.
Have checked the micro switch and that is good and also checked at connector under side panel-when I disconnected this connector and shorting the two terminals of this block that is wired back into the main loom it worked as expected so thought it was the micro switch ,however it only worked a couple if times by shorting at this connector -so is this possible an issue with the ecu?
Is there an easy way to just wire in the micro switch wiring from the brake pedal into a live feed when ignition is turned on and slice into the rear brake circuit.
Sorry this question is not too clear but basically rear brake pedal is not illuminating the light and not the micro switch at fault and the front brake will illuminate it-but it appears to work when ignition first turned on but then subsequently doesn't work.
Any ideas?

[Pete.]

It'll be the switch. I always thought that the ABS bikes all had a NC brake light switch. I found this out when my brake light switch failed and I tried to fit the one that came off my old ABS model. The light was on until I pressed the pedal then it went off. Further investigation showed that the non-ABS switch was normally open and the ABS one was normally closed.

[markwin]

Thanks Pete,That's what I thought initially BUT when I disconnect the connector from the brake light micro switch under the side panel I would have expected to be able to either turn on or off the brake light by shorting out the pins that go back into the loom-effectively bypassing the brake pedal switch.
I will check the wiring/switch with a multimeter for continuity/open circuit but would have thought that by shorting the other connection to the loom that would have operated the light.
So, either the circuit going into the loom is faulty or am wondering if the ecu module is playing up.
This bike is the one which has iabs and is not wired how a normal brake light circuit is but goes via the ecu .
Have done the Absectomy several years ago and all been good since.
Have just replaced the rear tyre and the brake pads and thought it must be something I had disturbed but because I have not used the bike for quite awhile I don't know for certain if this has anything to do with it.
Sorting a brake light switch/circuit should be pretty simple but as it goes via the ecu it makes it difficult to trace the problem.
Will start again with basics and work my way through but if it is the ecu I may have to wire it independently and hope this doesn't cause other issues.
Why BMW overcomplicated things for no good reason is completely daft,who ever thought servo brakes are necessary?.
Does anyone have a wiring diagram for iabs equipped r1100s? and where would it be best to find a suitable switched live feed ?
Might be over thinking all this !!
Any ideas gratefully received.

[markwin]

So, I have just removed the battery after taking off all the panel's to get to it and lifted the tank to gain acces to the wiring I did years ago-all connections are as good as the day I did them which is at least a bonus.
Before I went any further I temp reconnected the battery and the brake lights all work as normal-now I did disconnect the positive batt terminal for a minute or two BEFORE I did the above as thought it might just resett anything but on that occasion obviously it didn't resolve the issue hence further digging.
The thing is I have not found anything that was responsible but may have inadvertently fixed whatever was the cause OR the battery needed to be disconnected longer than the first time IF it was the resolution..
Don't know what caused the problem and don't really know why now working which is a bit of a worrie as its always nice to figure things out but if it reliably works shall take it as a win.
Hope when all put back it remains good or shall give it a Damn good thrashing ( ala Basil Fawlty).