Kostenlot's instrument cluster has developed a fault - the neutral light was coming on, then slowly dying after about thirty seconds. Now it doesn't come on at all. It's definately not the bulb or the housing: voltage at the positive feed tab is 1.37v and the input voltage (black/green wire) is whatever the battery says it is i.e. 12-13+ volts. Currently I'm pointing the Finger of Doom Possibility at the diode that feeds the light but... you never know. I have three spare early instrument clusters but no spare late one (single fuel warning light). Motorworks have secondhand ones but the price made my pension dissolve into gibbering fear and of course, James Sherlock is just taking the p!ss as usual.

Has anyone on this green and sceptic isle got a spare one that they're willing to part with for a fee, please?

Dai wrote:Kostenlot's instrument cluster has developed a fault - the neutral light was coming on, then slowly dying after about thirty seconds. Now it doesn't come on at all. It's definately not the bulb or the housing: voltage at the positive feed tab is 1.37v and the input voltage (black/green wire) is whatever the battery says it is i.e. 12-13+ volts. Currently I'm pointing the Finger of Doom Possibility at the diode that feeds the light but... you never know. I have three spare early instrument clusters but no spare late one (single fuel warning light). Motorworks have secondhand ones but the price made my pension dissolve into gibbering fear and of course, James Sherlock is just taking the p!ss as usual.

Has anyone on this green and sceptic isle got a spare one that they're willing to part with for a fee, please?

You can replace the gear indicator circuit board with one from one of your spare earlier clusters. It's the same part for all years and models.

https://www.realoem.com/bmw/enUS/showparts?id=0516-USA-07_1986_K589_BMW_K_100_LT_87_0506,0516_&diagId=62_0534#62111459238

How to replace: http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/gpi/gpi.htm

I was sort-of hoping someone would come along and say something like this. The GPI itself is working fine; it's just the bit of circuit that powers the neutral light that's gone AWOL.

Is the bulb holder properly inserted in the flexi circuit?  Occam's razor and all that.

I've had that problem with the lamps in one of my clusters.

If it is the gear position circuit board, I have one here that has a bad LCD that I could send for the cost of shipping.  The pond is in the way, so it might take a week or two.

Point-Seven-five wrote:Is the bulb holder properly inserted in the flexi circuit?  Occam's razor and all that.

I've had that problem with the lamps in one of my clusters.

The same circuit sends power to the start button when in N.

Does the bike still start in gear 0 when the clutch lever isn't pulled in? (Pulling in the clutch lever is the other source of power for the start button.)

Fixed. I had a GPI board with a knackered LCD display so I indulged in The Great Swaparound. Then swapped the pcbs back again just to be sure, to be sure. Thanks for the pointer Duck.

It's a new wiring loom that's being bench-tested before fitting to the bike, so my first reaction was that I'd done something wrong. It was only after I was absolutely certain it wasn't a fat-finger job that I suspected a pcb failure somewhere.