[iqraceworks]

I'm installing a boost gauge in my 07' 335i. At night when I turn the headlights on, I need 12v power to run to the gauge to light it up.

Where is the best place to get 12v power from when I turn the headlights on?

Any advice would be great..thanks!!

[Dx11]

Fusebox?

[ewicky]

Your questions was originally about switched 12V power, but then you're talking about lighting up your boost gauge with your headlight switch.
"Switched 12V power" is typically "switched" with wake-up, accessory, or ignition. What it sounds like you're looking for is running lights power.
Sorry I'm not being more helpful, but I'm at work right now. Just saying if you phrase the question more accurately, you'll get better responses.

[iqraceworks]

Originally Posted by ewicky

Your questions was originally about switched 12V power, but then you're talking about lighting up your boost gauge with your headlight switch.
"Switched 12V power" is typically "switched" with wake-up, accessory, or ignition. What it sounds like you're looking for is running lights power.
Sorry I'm not being more helpful, but I'm at work right now. Just saying if you phrase the question more accurately, you'll get better responses.

Yes...I'm looking for 12v power only when the head lights are on. I can tie into the ask tray light....but I was hoping that there might be something a little easier to get to than that.

[Serf27]

The actual light switch lights up with the headlights, check if there is a wire on its connector that illuminates the lights?

[hassmaschine]

Look up the ETM (BMW wiring diagram).

[iqraceworks]

Originally Posted by Serf27

The actual light switch lights up with the headlights, check if there is a wire on its connector that illuminates the lights?

Thanks, I will look there...and then also I thought about the trunk button down on that side by your feet...it lights up when the lights are on. It should be easy to pop that out and get to the wires.

[nthnthnthnth]

Not sure if the license plate lights are 12V but you could tap into that. Or use the cigarette lighter wiring as a power source with a switch that taps into the license plate light wire to triggers on/off with the license plate lights.

[Serf27]

I think OP is looking for a power source near where the gauge will sit.

[Dx11]

Again. Fusebox. Add a fuse. so easy.

[haaken675]

You can probably tap off of the light switch itself. These cars are too smart for their own damn good however, so i'm unsure not having done this myself if the difference in voltage will trigger any sort of alarm bells.

[Serf27]

Originally Posted by haaken675

These cars are too smart for their own damn good.

The headlight switch or trunk switch would also be good because the light for the gauge brightness itself would adjust when you adjust all other lights on the cluster.

[BSM n54iS]

Get the P3

[gbalthrop]

[QUOTE=iqraceworks;28557025]I'm installing a boost gauge in my 07' 335i. At night when I turn the headlights on, I need 12v power
to run to the gauge to light it up. Where is the best place to get 12v power from when I turn the headlights on?

Originally Posted by iqraceworks

Yes...I'm looking for 12v power only when the head lights are on... I thought about the trunk button down on that side by your feet...
it lights up when the lights are on. It should be easy to pop that out and get to the wires.

Questions:
1) What are the Last-7 Characters of your VIN so we can provide ISTA wiring diagram ScreenPrints that are correct for YOUR Vehicle?
2) Does the aftermarket gauge use an LED or resistance bulb?
2a) Does the Gauge Mfr suggest what type of light and Amp Draw it has?
3) I presume you want it to be "Dimmable" as are other Instrument/Locator lights?

All the Gauge, Steering Wheel and Locator lights on your E9x receive power from "58G" variable (Dimmable) output from FRM.
NOTE: ALL 58G wires from FRM, either connector, are Gray/Red. Last ScreenPrint shows Connector at Interior Rear lid release switch.
Gray/Red wire at X1295/1. See attached ISTA ScreenPrints for LATE (built > 3/1/2007) 2007 335i E92.

The lights Lit/Dimmed by "58G" are LOCATOR lights ONLY, and NOT the lights such as reading lamp itself that is NOT dimmed.
George

[iqraceworks]

Last 7 digits of VIN are P032929

It's a Autometer boost gauge, it's got a small incandescent bulb. I checked the paperwork it came with and it doesn't list an amp draw for it, but I'm assuming is very small.

I honestly don't really care if it dims with the interior lights...I just want to be able to see the gauge at night.

Is there any issue with just taping into the positive wire than goes to the "open trunk" button on the driver's side near the floor? It lights up when you turn the lights on....so that should work great.

Thanks!

[Serf27]

It should be fine if you tap into that wire.

[Yotaismygame]

From what I've read on this forum in the past the center console has everything you need.

[gbalthrop]

Originally Posted by Yotaismygame

From what I've read on this forum in the past the center console has everything you need.

What if "One's Needs" exceed the capacity of the center console???

[iqraceworks]

I ended up getting the power from the cigarette lighter LED light. Easy to get too....lots of room to tap into the wires, piece of cake.

....now I have to figure out how to make my auto-meter boost gauge accurate....it's around 2psi off and reads 1"hg vacuum when the car is off. After searching Google....sounds like a common problem with those cheap auto-meter gauges ..

[rotarypower101]

Is there a switched +12V source somewhere close to the battery in the rear right side of the E92 that can be used?

Have a trailer brake that needs 12V ~max 8A

Is there a good existing switched source for this in the rear? Or at least an easy to access +12V switched source to drive a relay near the rear cargo area?