Extra plug on a 1980 A-model

I have a 1980 A model I'm trying to put back together after the previous owner took it apart. I think I have all of the wiring figured out...... I THINK. AS I was putting the regulator/rectifier on I couldn't find one of the plugs for it on the main harness. Looking at it and the diagram today, I relized I had made a mistake on a different plug, and used the plug for the regulator to the main harness for a different location. When properly pluged in, I have another plug left over that I can't figure out a use for! It's under the fuse box near the regulator/rectifier and the ignition module. It's a for pin plug with three wires in it: white with red tracer, blue, and red. I can not find where it plugs in to. Is there possibly a missing component that I don't realize is missing? Could it be just an extra plug thats not used on this model? Anyone have an idea of what I'm talking about? Thanks everyone.

I don't have that connector on my 1980 B2 chassis. I cant find it on any diagrams either.

If it was a US model there may have been a reserve lighting device installed there. It may be that someone has removed the indicator self cancelling unit? I think both of these units would mount under the battery tray.

I've checked the diagrams and neither have a 4 pin connector on the white with red trace circuit.

just thinking of the top of my head, have you got the isolator switch on the side cover plugged in, could be that.
i would look at my bike but its buried behind 3 others at the mo
Ian

As far as I can tell the reserve lighting ynit is in place and is plugged in. I know ther is at least one component mounted under the battery tray, I'll have to look closer for a second component under there. When you refer to the isolator switch I assume you mean the key switch that shuts off the electrics and opens the seat latch. I do have that in place and plugged in. As far as I know mine is the standard US model. Is there a sure way to verify which model it is?

A little added information: The plug has power to two out of four of the prongs.

Thr red wire is always 12 volts + and from what I can see on most of the wiring diagrams the white wire with the red tracer is a 12 volt + coming from the fuse panel so in other words a fused 12 volt supply. That being said, if you put your tester on the white wire with red tracer and start pulling the fuses out till you get a zero reading, then check that fuse for identification it might help answer the question.

that's my 2 cents for today.
Kawboy