I have an M41 gearbox with the long top (standard 1800 stuff, only it's on my 122 which was modified to fit it). I cannot find the connection on the gearbox where the wire for the reverse light attaches. I can feel the cap on the rear top of the gearbox which covers the end of the selecter rods (as in Haynes Manual p105 image 5.6a). What I don't feel is the male connection where my wire should attach on the passenger side. This is the wire that comes up into the engine bay and attaches to the 3-prong reverse light relay.

Any advice about where this connection is?

Thanks.
Colin