I'm installing an AEM CD7 digital dash, and the display is supposed to dim automatically when you turn on your headlights.
To do this, you need to tap into a 12V source that is only powered when the headlights are powered.

Where do you guys think would be the best place to tap into in the dash area? I don't recall there being somewhere on the cluster circuit board that would fit my needs, although that would be ideal. Headlight fuse?

 

I used the positive wire for the ash tray illumination bulb for my boost gauge, this comes on with the running lights and headlights and would serve your purpose. I believe there is also a trigger wire for the radio to dim it but I don't know which one it is.

 

There should be one going to the cluster itself. Also could use a wire going to the dimmer switch.

Dale

 

I think I may have explained poorly
I'm not looking for a 12V source that will dim along with the interior lighting
I'm looking for a wire that is 0V with the car running and headlights and/or running lights off, but is +12V with the headlights and/or running lights on. I honestly don't care whether it follows the headlights or running lights, but it has to be one or the other

Anyone know specifics?
I don't believe the cluster has anything that I can tap into, but there must be one in the dash area

 

The radio illumination dimming trigger is 12V on / off I believe.

 

I use the red w/ black stripe wire on the green connector on the fuse box. This is not connected to the dimmer switch but has voltage when the lights switch is on.

This is the wire that I use for the dimming function on the Defi gauges. If you use the ashtray light it causes the gauge to flicker.

 

You guys are both right
I tested the radio illumination trigger (which is red/black in the harness and orange at the deck) and it should do the trick nicely.
Thanks guys

 

+1

Don't use the illum wire from the radio harness. It's a PWM signal and will cause your gauge lights to flash on and off at a steady pace. Ask me how I know...