[strictlypersonl]

The red/white wires are intended for gage lighting. Connect it to the R/W wire of the pigtail coming from the tach. The black wire should be connected to the case, together with the pigtail's black. I usually throw in some-male spade-to-stud adapters in the bag but if you need some, I'll send you some.

And I'll make the instructions a little less ambiguous...