Speedo dead brake failure light flashing

[Uncle Ian]

Hi All,
I have a 2002 R1100s (iABS), The bike has a long term defect that I am attempting to resolve.
When riding the bike the speedo doesn't work, and the Brake failure light flashes at 1 Hz.
Servo function is fine,GS911 shows no faults, and was very useful for testing the wheel sensors -so it has paid for itself already.
The rear wheel sensor was not showing wheel speed when the rear wheel is turned, However when I jump the rear wheel sensor to the front wheel electrical circuit- it is working, Hence the sensor & it's air gap are correct
I have continuity between the rear wheel sensor up to the ABS Plug, And I can feed a pulsed signal from the ABS plug to the speedo And I get a speedo reading. This seems to point to an issue with the plug connection or internal electronics of the ABS modulator. Then this bit really beats me - About a month ago I rode the bike home in 40 deg C heat first gear for 20km on the freeway(not by choice),And yes everything fired up & ran perfectly for the next 7 km, before going back into it's coma.
Short of waiting for further global warming any further guidance would not go unheeded.

Thanks,
Uncle.

[Uncle Ian]

Update:
I have pulled out the abs modulator, and separated  the circuit board from the hydraulics,, I get electrical continuity to the PCB, so sadly the plug connections are ruled out, looks to be a PCB dry joint or failed electronic  component, My options are;to replace the whole unit, for a minor PCB fault.
Or use a GPS as a speedo., leaving me the servo assisted brakes without ABS.

[Jughead]

Instead of checking continuity, check for a short down to ground on one of the wires.

My guess is that you have a chaffed portion on the wiring harness that is grounding the sensor wiring.  This normally happens just below the left corner (as seated on the bike) of the battery bracket.  The brackets tend to rust and then chaff the harness.

[Uncle Ian]

Thanks Jughead,
Just got home & went & checked out the bike straight away, no bridges back to Earth on either the sensor itself, nor the sensor to modulator harness.
I see exactly what you mean about the wire chaffing, The outer wrap was a little broken up but the insulation looks fine.
Your suggestion certainly makes sense. I'll reassemble everything at the weekend, and check with everything sitting  back in place.
Is it just me, or do these bikes look like I did the wiring?

Thanks Again, I will let you know what I  find

[Jughead]

It may be worth your while to remove the battery bracket and unwrap the wiring around that area and then check the wiring with a magnifying glass.  You may think I am joking, but here is an example of what I have found, more than once.

While everything "looks" ok, this nick (red arrow) caused this bike to start up automatically as you turned the key on, and then held the start solenoid in so that the starter ran all the time.

Green arrow is the nick that caused the indicators to come on at really arb times.

[Uncle Ian]

I take that as great advice, and since everything is clear of that area, it will be a good time to have a snoop around and a tidy up.
I will check the wires & rewrap them.Really appreciate your efforts in helping out, photo's etc.
Cheers Jughead!

[Jughead]

Pleasure!

[Uncle Ian]

 Replaced the ABS modulator, with a second-hand unit from my local service guys, all problems resolved. Bleeding those units is a reasonably long winded process.
That's it! I owe myself a beer, I also owe Jughead a beer.