legacycentral bbs

So I recentley installed a Autometer boost gauge. Spliced the power wire into the ash tray light and the ground... well to a ground. The only issue is that when I dim the dash lights the Boost gauge gets brighter, and when the dash lights are on the brightest setting the boost gauge doesnt illuminate. Whats causing this to happen?

Did you accidentally mix up the wires?

The dash lighs do not use a normal ground. They are grounded through the dimmer switch.

What is happening is that when you dim the dash lights your pulling that wire up closer to 12v. So the main dash lights are at 12v (battery) minus ~9v (dimmer) = ~3v (dim bulb). But your added gauge is at ~9v (dimmer) - 0V = ~9V (bright bulb).

When you turn the dash lights up your pushing that wires voltage down. Main lights 12v - ~3v (dimmer) = ~9v (bright bulb). Boost gauge is ~3v - 0v = ~3v (dim).

Basically, take the wire you have on the direct ground and move it to the switched illumination wire. It will be the wire that stays at 12v no matter where the dimmer is turned to. I'd tell you the colors, but I don't have my diagrams handy.

So just move the ground to the switched illum. wire. Where is the switched illumination wire located?

Tie into one of the illumination wiring points for any switch or light.

Alright having a noob moment and need to clear this up.

Im looking at the wiring schamatic for the interior lights. It shows "Illumination Control Module" 6 wires come out of it 1 being a ground.

So do I leave the hot wire I have for the gauge spliced into the hot wire of the ash tray light and move the ground to the ground on the Illumination control?

No,

You want to leave your switched 12v source tied in like you have it, and then tie into pin 2 (YL - Yellow Blue) for your ground. If you do this, the boost gauge light should dim with the other lights.

Alright got it, sorry about that. Ill give it a go and see what happens.

Thanks Guys

YAY! The gauge dims with the lights now! Thanks for the help!