How do I tap into the light dimmer circuit? - Toyota Yaris Forums

LtNoogie · 02-25-2009, 10:26 PM

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 · 02-26-2009, 12:19 AM

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 · 02-26-2009, 12:33 AM

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.

eTiMaGo · 02-26-2009, 12:47 AM

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

)

PETERPOOP · 02-26-2009, 12:53 AM

subscribed

m911gt · 02-26-2009, 01:25 AM

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 · 02-26-2009, 01:40 AM

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 · 02-26-2009, 01:49 AM

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

http://www.amazon.com/Universal-2-Ch.../dp/B001ES64MK

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

m911gt · 02-26-2009, 01:50 AM

Quote:

Originally Posted by 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?

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

eTiMaGo · 02-26-2009, 02:18 AM

Quote:

Originally Posted by LtNoogie

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

http://www.amazon.com/Universal-2-Ch.../dp/B001ES64MK

http://www.autometer.com/cat_accesso...l.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 · 02-26-2009, 06:36 PM

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 · 02-26-2009, 11:43 PM

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 · 02-26-2009, 11:49 PM

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

02-25-2009, 10:26 PM	#1
LtNoogie View User's Garage Drives: '08 Bayou Blue LB AT Join Date: Oct 2008 Location: West Hills, CA Posts: 2,517	How do I tap into the light dimmer circuit? 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 __________________ aFe Intake \| Blitz Supercharger \| Megan Header \| TRD Exhaust \| NST Pulley Set TRD Shocks/Struts \| Tanabe NF210 Springs \| TRD Sway Bar \| Motegi TRAKLITE wheels \| Kuhmo Ecsta XS R1 Concepts slotted rotors \| Carbotech 1521 brake pads \| stainless steel brake lines \| Seibon vented carbon fiber hood

02-26-2009, 12:19 AM	#2
Doc Zaius Lurker supreme! View User's Garage Drives: old and boosted! Join Date: Nov 2006 Location: Ottawa, ON, Canada Posts: 792	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! __________________ 2006 Red Blitzed RS 5-door

02-26-2009, 12:33 AM	#3
LtNoogie View User's Garage Drives: '08 Bayou Blue LB AT Join Date: Oct 2008 Location: West Hills, CA Posts: 2,517	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. __________________ aFe Intake \| Blitz Supercharger \| Megan Header \| TRD Exhaust \| NST Pulley Set TRD Shocks/Struts \| Tanabe NF210 Springs \| TRD Sway Bar \| Motegi TRAKLITE wheels \| Kuhmo Ecsta XS R1 Concepts slotted rotors \| Carbotech 1521 brake pads \| stainless steel brake lines \| Seibon vented carbon fiber hood

02-26-2009, 12:47 AM	#4
eTiMaGo vroom vroom View User's Garage Drives: lil red 5-door Join Date: Sep 2006 Location: Bangkok, Thailand Posts: 7,744	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 ) __________________ The price of freedom of religion, or of speech, or of the press, is that we must put up with a good deal of rubbish. - Robert Jackson Bye bye 1NZ...

02-26-2009, 01:25 AM	#6
m911gt Carless in Chicago View User's Garage Drives: 08 Blk LB Join Date: Oct 2008 Location: Chicago Posts: 2,479	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. __________________ Wanted: Forced Induction Some say that he is the secret love child of Ferrari and Porsche, and others say that he would lap James May twice in a 1/4 mile drag race. All we know is that he is called The Stig.

02-26-2009, 12:53 AM	#5
PETERPOOP View User's Garage Drives: 08 white liftback Join Date: Oct 2008 Location: Oahu Posts: 3,674	subscribed

02-26-2009, 01:40 AM	#7
LtNoogie View User's Garage Drives: '08 Bayou Blue LB AT Join Date: Oct 2008 Location: West Hills, CA Posts: 2,517	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? __________________ aFe Intake \| Blitz Supercharger \| Megan Header \| TRD Exhaust \| NST Pulley Set TRD Shocks/Struts \| Tanabe NF210 Springs \| TRD Sway Bar \| Motegi TRAKLITE wheels \| Kuhmo Ecsta XS R1 Concepts slotted rotors \| Carbotech 1521 brake pads \| stainless steel brake lines \| Seibon vented carbon fiber hood

02-26-2009, 01:49 AM	#8
LtNoogie View User's Garage Drives: '08 Bayou Blue LB AT Join Date: Oct 2008 Location: West Hills, CA Posts: 2,517	Here are my choices if I cannot find a way to tap into the car's dimmer. http://www.amazon.com/Universal-2-Ch.../dp/B001ES64MK http://www.autometer.com/cat_accesso...l.aspx?vid=185 __________________ aFe Intake \| Blitz Supercharger \| Megan Header \| TRD Exhaust \| NST Pulley Set TRD Shocks/Struts \| Tanabe NF210 Springs \| TRD Sway Bar \| Motegi TRAKLITE wheels \| Kuhmo Ecsta XS R1 Concepts slotted rotors \| Carbotech 1521 brake pads \| stainless steel brake lines \| Seibon vented carbon fiber hood

02-26-2009, 06:36 PM	#11
largeorangefont Break'em off some. View User's Garage Drives: 07 Yaris LB, 04 Cobra Join Date: Jan 2007 Location: So Cal, OC Posts: 854	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. Last edited by largeorangefont; 02-26-2009 at 06:52 PM.

02-26-2009, 11:43 PM	#12
CTScott ULTIMATE View User's Garage Drives: 09 5dr LB, 2x 08 3dr LB Join Date: Oct 2008 Location: USA, CT Posts: 13,460	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.

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