markell27

In my attempt to install a boost gauge on my 95 240sx I'm left a little stumped.

First, I bought a Garrett mechanical boost gauge that has three wires (orange - illumination; red - 12v; black - ground). Pretty straight forward and used the cigarette lighter for all wires. What I found was gauge light is always on when ignition is on. So what is the point of the illumination wire? Hell, I disconnected the orange wire and gauge remained lit. I figured it would come on with the headlights since I was using a dimmer/illumination connection. Is this just because its a LED gauge?

Second, I got some professional advise for the t-fitting location that I could tap into the existing boost controller vacuum hose. Therefore, I added the t-fitting under the dash near the steering column. Now both the controller and gauge shows only vacuum (doesn't go above zero). I'm sure the simplest answer is a boost leak. I've checked my work on this one line and no issues. So my question is: Could this be an issue of having one hose tapped for a boost controller and boost gauge that also includes an in-line filter?

This shouldn't be so hard, but I appreciate your help.

Lord Humongous

Contact Jay on here. He did mine and it works great

nftuatn

i dont think jay could instate something...he may be able to install it...

Lord Humongous

He is pretty much magical

jdm monkey

what vacuum hoses are you using? make sure to not use the cheap silicone like ones from APC.

what gauge are you using? sounds like prosport gauges

Slomar

Sounds like you wired it up to the 12 volts that the cigarette lighter gets when the ignition is on and not the 12 volts that power the illumination. Use a multi-meter and test the wires with your lights off and then with them on to find the right one. Not too sure about the boost controller issue, but i would switch it back to how it was when it worked, and hook your boost gauge up to its own vacuum source.

Jay

Dims with +12V ILL most likely.
+12V Switched, +12V ILL, and Ground can all be easily found in the Stereo harness.
T your gauge's vac line into the FPR vac line.

Good day sir.

Fabrik8

Usually the 12V wire is used to power the backlight that lights the gauge face, and the illumination wire is used to sense the dash illumination to dim the backlight. Basically one is a power wire and one is a voltage sense wire.

markell27

Without a multimeter I used a test light to see what wire went hot when the headlights were turned on and what wire went hot when the ignition was turned on. I tried two power wires (radio - blue and cigarette lighter - orange). Again gauge light comes on as soon as ignition is on, but don't these gauge lights work off the illumination wire for the light to come on?

T-fitting for boost controller is connected to hose between intake manifold and fpr. It worked fine before all this.

The gauge hose is that piece of crap clear plastic stuff.

The gauge is made by Garrett. I think it's the only one they make.

markell27

Thank you! So I'm not retarded...