I have the following questions for installing a boost gauge

Where did you guys happen to ground the wire at?
Where did you guys splice into for the 12v source (what color wire)?
(have no access to a volt meter)

pics. if possible.

You plug in the harness behind the radio. If the harness to the gauge it cutted then you will have to extend the wires it to the 2 pin harness behind the oem radio.

to the radio, but i just wired mine into my factory boost gauge wiring.