new A4 member trying to wire boost gauge

[Asharp27]

ok, so i'm trying to install my stuart warner boost gauge and i don't have a test light so can anyone just tell me which wire is positive? i assumed it was the blue one because the other one's black so .. i used basic reasoning but ive been reading the DIY's and can't seem to figure it out. I want my gauge to work with the dimmer so that's why i'm trying to wire it to the AC roller. TIA

[B6 Dude]

No downloadable instructions?

[[email protected]]

You wire it to the blue wire with grey stripe in the headlight switch.

Instructions are here: http://www.podi.ca/Installation.aspx

The wiring steps are the same for your gauge

[[email protected]]

You need to tap the BLACK wire. I had this same problem yesterday when wiring my boost gauge and made the mistake of wiring it backwards. For some reason, the BLACK is positive and the BLUE is negative. Trust me!

Hope this helps!