Hello all.

i bought a couple after market gauges one water temp wand one boost.. i was wondering if someone can point me in the right direct as to where to wire them up so the turn on when the car is on just like everything else.

body: 87 S4
engine: 91 TII
Ecu. Haltech Sprint RE

do i have to wire them to the ECU? or is there an ideal place in the chassis harness that i should use?

please and thank you

 

Use an aftermarket relay to send power to your aftermarket gauges. You'll need constant power from the battery and you'll need to tap into a wire that gets power with the ignition key. There sb wires on both the driver and passenger side that are energized when the key is on.

 

You can tap into constant(Blue/Red), ignition(Blue/White), Illumination(Red/Black) and ground(Black) from the wires in the stereo.