I did a search. A lot of threads on hooking up the boost hose but the source for the dimming illumination is a bit dated ('03). The threads indicate that the stock radio harness has a "pigtail" for the stock Lamco boost gauge illumination.

Does this still hold true for my '06 WRX? Is the illumination circuit for the stock boost gauge pre-wired, and, if so, where did they hid it? If not, where should I splice the into so that it dims along with the gauge cluster.

Thanks

 

if no one responds try getting a hot wire tester.. you just hook it on a ground and then touch the needle end to each connection and when the ligh turns on thats when you have power.. so you will want to make sure the light turns on on the wire only when the headlights are on..

 

yes it's true for the 06. i connected to it when i installed my oem gauge.