Hi all,

Bit of a weird one to throw out, and hoping someone can help.

I've now had two 1993 BMW K1100LT ex police bikes in the man cave for electrical gremlins.

I've narrowed things down, I think, to a mismatched right hand combination switch, but need some help identifying the corresponding wires on the main harness to test my theory.

Combination switch has the following:

Blue/Yellow + Brown = Turn Signal switch
Black /Yellow + Black/Green = Start Button
Green/Yellow + Green = Kill lever
Brown/White + Brown = Turn Signal Cancel

Harness has the following:

Black/Brown
Blue/Brown
Green/White
Green/Black
Blue/Yellow
Green X2 in one connector
Red/Yellow
Green
Brown/Blue

I'd appreciate the input of your collective wisdom on this head scratcher.

Cheers, Alex.

Hey Alex, how about sharing the gremlin symptoms and see if we can identify what's going on. Also, can you list the primary colour in upper case and the secondary colour in lower case as it makes it easier to understand the wiring

Harness wiring first (L-R) looking at the connector:

PIN 1            PIN 2                  PIN 3                    PIN 4                  PIN 5            PIN 6
BROWN         BROWN/blue         GREEN/white          BLUE/yellow         BROWN/blue    Not used


PIN 1            PIN 2                  PIN 3                    PIN 4                  PIN 5            PIN 6
Not used       Not used             GREEN x 2              RED/yellow          GREEN            BROWN/blue


Handlebar switch wiring (L-R) looking at the connector:

PIN 1            PIN 2                  PIN 3                    PIN 4                  PIN 5            PIN 6
BLACK/yellow  GREEN/yellow       GRAY (loop)            GRAY (loop)        BLUE/yellow    BLACK/green


PIN 1            PIN 2                  PIN 3                    PIN 4                  PIN 5            PIN 6
GRAY (loop)   BROWN               GREEN                   BROWN/white       Not used        Not used   


Obviously right combination switch pinout and wiring schema don't match the harness on the bike, but with that in mind, gremlins are as follows:

Run/Off switch doesn't work
Can't indicate right
Can't cancel turn signals
No start when pushing starter button

I also suspect that the gear position sensor is dead, which will be causing further ugliness.

KiwiK100 wrote:Hey Alex, how about sharing the gremlin symptoms and see if we can identify what's going on. Also, can you list the primary colour in upper case and the secondary colour in lower case as it makes it easier to understand the wiring

KiwiK100 wrote:Hey Alex, how about sharing the gremlin symptoms and see if we can identify what's going on. Also, can you list the primary colour in upper case and the secondary colour in lower case as it makes it easier to understand the wiring

Right hand combination switch part number is 61.31 2305 233

Main harness part number 2305600

Looking at your wiring diagrams of the connectors it appears that there are a number of harness pins that have wires noted by their colours but in the handlebar connector the corresponding pin is empty. And visa versa. Clearly something is amiss here, but you already know that. 
I did a quick search on the part number for the combination switch and it suits a Canadian spec bike of your model and vintage. What that shows is the lights are hard wired on but whether it is the original combination switch or it was added when the Police spec equipment was removed is anyones guess. 
There have been a few posts on the forum from owners in Aussie with Police spec bikes and maybe they will chime in, although it may mean chiming in on yourself, as most of the posts are yours 
I had a look at the wiring diagram in Clymer and couldn't even start to get a match on anything so a real curly one to sort out. 
Has the bike ben a runner since you've owned it? Maybe it has a completely different main harness? I believe some bikes were fitted with a 'Services' harness.  I think I'm probably telling you stuff you already know however. 
Good luck, I'll be interested in the outcome.

Alexander McCarthy wrote:Right hand combination switch part number is 61.31 2305 233

That number matches the part listed for both the '90-92 K100RS and the K1100RS/RT Canada versions in the MAX BMW parts fiche.

Alexander McCarthy wrote:Main harness part number 2305600

That squares with MAX's number for a '93–  K1100LT/ABS