K-series SOBeemer question

Sorry this is very dumb, but anyway:

I've got some switches from a K-series crash pad I want to re-use on my R80. They were old and cruddy, but strip down easily and have cleaned up nicely.

Thing is, I can't work out what the one labelled "ABS" is for. Now I've cleaned it up (not yet reassembled it), it looks like it's more like a button (momentary) than a switch. There's no bulb fitted to it (although there's a red lens), and just two contacts.

I've never owned anything with ABS, so please can someone tell me what that switch should do on a K-series bike?

Many thanks,


PS: I've got manuals for R-series airheads (Clymer and HBoL), but neither cover ABS systems, as I don't think the airheads ever had them.