Wiring the headlamp foot switch 67 riv

Hi i need a bit of help .where does the bottom terminal on the headlamp foot switch go thanks stuart

 

The one wire plug is power from the headlight switch. The other 3 wire plug goes to the lights

 

There are only 3 wires going to the dimmer switch connector according to the '68 schematic Steve ? o No:
Brown and Light Green go to bottom contacts, and the Light Blue goes to the top contact - assuming '67 has the same wire colors, and connector?
Light Blue goes to headlight switch, Light Green goes to the hi-beam dash cluster indicator and the headlights, and the Tan colored wire also for headlights. :TU:

 

I gave you the link to the online 1967 Buick Chassis Service manual in one of your other threads.
You will also find wiring schemes there:

Click here :Comp:

 

For some reason I was thinking I saw 3 wires on the large plug. Old age I guess