Mercy tach and speedo HALP!

[Meatbasher]

Anyone want to take a stab at how this gets hooked up?

I know know brown is from the Mercontrol for the tach, white is hot and black is ground.

I had had things labeled but after 8 years the pencil wore off and my labels were just a bunch of blue tape with no words.

Speedo is on the right. Tach on the left. The 2 positive post have me scratching my head.