How do I tap into the light dimmer circuit?

[LtNoogie]

I'm installing Autometer gauges and have found that the LED backlight illumination is too bright at night. Does anyone know where to tap into the dimmer-controlled circuit?

My friends and I are guessing that the car uses pulse width modulation to dim all the illumination LEDs throughout the dash and AT shift console. Autometer sells a little box that will dim their meters but I'd rather control the light output from the factory dimmer switch.

Thanks

[Doc Zaius]

Do you usually dim your regular dash lights with that dimmer? If you don't, then you might run the risk of having your dash lights too low so that your new gauges are comfortable. Just a thought...!

Oh, and I still owe you logos!

[LtNoogie]

Yeah, who needs to add blue LED interior lighting when you've got the C2 gauges at full brightness. I probably look like a smurf to people outside the car.:laugh:

[eTiMaGo]

I'm at work right now and not able to look up the wiring diagram, but I can confirm that it uses a PWM dimming system (look at some of the night-time videos I took, the gauge cluster is flickering because of the lack of sync with the camera's refresh rate :smile:)

[PETERPOOP]

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[m911gt]

when my friend and i wired up my tach the other weekend, we took everything from the dimmer circuit but for some reason, when we went to dim the tach light the needle went wild. we then took power from a different source and i am a little sad to say i cannot vary the intensity of the gauge light.

[LtNoogie]

I don't know your tach but it sounds like you ran the +12V for the electronics into the dimmer circuit. The electronics need a solid 12V. There should have been a second wire that went to the dimmer circuit. How hard is it for you to reverse the wires?

[LtNoogie]

Here are my choices if I cannot find a way to tap into the car's dimmer.

http://www.amazon.com/Universal-2-Channel-Lighting-Controller-Incandescent/dp/B001ES64MK

http://www.autometer.com/cat_accessoriesdetail.aspx?vid=185

[m911gt]

I don't know your tach but it sounds like you ran the +12V for the electronics into the dimmer circuit. The electronics need a solid 12V. There should have been a second wire that went to the dimmer circuit. How hard is it for you to reverse the wires?

not hard at all, however we tried that as well and came up with no success. :iono:

[eTiMaGo]

Here are my choices if I cannot find a way to tap into the car's dimmer.

http://www.amazon.com/Universal-2-Channel-Lighting-Controller-Incandescent/dp/B001ES64MK

http://www.autometer.com/cat_accessoriesdetail.aspx?vid=185

The first one's pretty cool, 2 channels and you can mount it pretty much anywhere... Or you might get better value by using a computer fan speed controller, they run off 12V as well, and you'd get 4 channels!

[largeorangefont]

You can go to Radio Shack and get a variable resistor or rheostat. It is much cheaper than the autometer solution.

You can then run the the gauges lights to the rheostat, and then to direct power and adjust the lights to you liking, or run the resistor to the interior lights.

If you do it that way you can adjust the new gauges to the brightness level you want them, and then adjust ALL dash lights as a whole. Just hide the rehostat under the dash.

You can find them at Radio Shack for a few bucks.

[CTScott]

Only the speedometer is dimmed using PWM. The light control rheostat has two 0-12 volt analog outputs that are supplies to the HVAC controls and to the combination meter. The beige wire is the dimmer feed to the HVAC knob lights.

If you pop the fuse panel compartment you can reach up and unclip the connector for the light control rheostat to get at its wires.

[Tamago]

a resistor for $.20 from radio shack would solve your problem :)