[bsimonson]

I spent some more time working on the brake lights the other day and could verify that the contact I first thought it was (see picture above) indeed is the connector to the brake lights. Wiring the brake light switch to the black/green wire made the lights come on when I press the pedal.

What I learned was that if you want to measure for connectivity to the rear lights, you need to disconnect both left and right connectors or otherwise they are grounded and the measurements will be inconclusive.