t25 auto starter motor connections

[ceetee25]

over a period of time i have changed my starter motor twice and solenoid once. the original had a red/black wire and a red/white wire attached to what i thought was 3 terminals on the original solenoid. Subsequent changes only came with two spade terminals co joined so nowhere to put the red white wire. needless to say i taped it and didnt bother and all seems ok but does anybody out there on the interweb know where this red/white wire goes and more to the point what does it do?
should be a picture attached somewhere