[sroby]

I am tying to wire my boost gauge. Its a basic mechanical by new south redline edition. 3 wires. black for ground/ red for 12v ignition on/ yellow wire for dimmer. seems strait forward. sourced the 12v to the red with blue stripe. under dash from main wire loom. Rally sport website shows the similar write up. However they use the violet or purple wire on frs harness for 12v red on gauge. Black for ground. I get it. However Yellow for dimming I cannot source where I need to connect Yellow for the gauge to dim with the dimmer frs light control. It seems no matter where I attach it the damn gauge wont dim. FRUSTRATED to say the least.
I was reading through countless pages last night. I'm guessing this is controlled by pcm. I know I am not the only one to ever wire up a mechanical boost gauge no data logging no electric just plain ole style gauge I am pulling vacuum from the back of the sprintex, up to the gauge on my blockhead pod. I have read that it might be possible to tab the yellow dim wire from gauge to light dim wire off of radio harness. Can anybody who has performed this please give me some insight on where to tap the yellow dim wire from gauge to frs so boost gauge light will dim with instrument gauges. Thx for input. Steve