I need to know which wires are which on the 4 pin power harness, red, black, white and blue.
Red: 12V Power
Black: Ground
White: 0-5V output
Blue: Serial output
so if i’m just using the gauge with the sensor, i just use the power and ground?
yes
Correct… but make sure not to hook up the blue to anything unless your running the aem ems.