Thanks Gordon, that was one of the first places I checked... Don't get the FTC LTL comment... must be an inside joke...
Pat, great thought, unfortunately there is nothing for you behind door #3 HA!
Looks like the steeler installed a AS-5NB. no snipping or bridging involved. it simply taps into the bike... per the install instructions "Autoswitch only taps into existing lines and does not affect any electrical circuits."
In the photo, the Orange wire from the Autoswitch was connected to the Green wire...
I hope that JZEILER (John) will also jump in as he knows a lot more than me about the specific wiring of the k1200LT.
Because I am familiar with wiring of K1200RS, I will give it a try... meanwhile you will have some more ideas.
Not being on site to do more electrical tests, I see 3 possible paths to eliminate variables here:
(1) either the cancel button just happened to become intermittent (sticky, hard) over time. I have seen this problem on similar switches for many BMW models between 2001-2004. This can be tested in a static manner with right switch assy unplugged (pin 1 is CANCEL having Brown/White wire ..AND.. Pin 10 is the common Ground having Brown wire). You are basically testing for continuity between these 2 when CANCEL is pressed (Ohm function with switch unplugged).
On a 2005, the switch connector should look like 2 attached pictures. On all K1200RS, this connector is located in lower electrical junction box (under tank), HOWEVER for the K1200LT (2005) I am not 100% sure of location: my BMW shop manual (on CD) shows it under nose fairing under/below windshield electrical motor (see last attached photo / diagram).
(2) NEXT Possibility: the wiring between CANCEL (at switch junction on harness side) and the "smart" Flasher Relay is damaged (Brown/White wire from connector goes to Pin 4 of the flasher Relay.
(3) NEXT Possibility: The electronics in the Flasher Relay has been damaged by some recent work. This is not an ordinary simple flasher Relay so you cannot just replace with an automotive unit. This is the last troubleshooting option as I do NOT see a high probability (given that other flasher functions appear to work... If I understand your post)