LEDs in gauges dimming question

mighty mouse · 06-07-2010, 03:38 PM

I have 3 autometer sport comp gauges with the autometer drop in LED bulbs wired to the little light in the cup holder. When I dim the gauge cluster, the LEDs dim the opposite of the cluster. For example, as the cluster gets brighter, the LEDs get dimmer, and vice versa. I tried flipping the bulbs around, which didn't change anything. Would reversing the wiring help? I don't see the difference between switching the wiring and switching the bulb, but this has me stumped!

jnshk · 06-08-2010, 02:43 PM

It's been a while since I messed with the dimmer circuit, but I think you're tapped into the wiring on the wrong side of the dimmer circuit if you want to gauges to dim in synch with the dash gauges.

If I remember right, the light in the cupholder area is not intended to dim with the cluster lights but rather to stay the same brightness, however the LEDs are more sensitive to changes in voltage/current which may be what gives you the unexpected dimming.

If you connect to the variable illumination circuit and then directly to ground, you will notice that the dimming probably occurs in reverse (much like you are experiencing). If I recall correctly, there are three wires involved in the variable illumination circuit (a constant 12 volt, a variable voltage, and a ground?) and you need to tap into two of them at the switch (or both wires that run to the switch at one of the other variable bulbs).

mighty mouse · 06-08-2010, 10:21 PM

ok that makes sense to me. Thanks for the input!

06-07-2010, 03:38 PM	#1 (permalink)
mighty mouse Member Join Date: Jun 2007 Location: NH Posts: 1,647	LEDs in gauges dimming question I have 3 autometer sport comp gauges with the autometer drop in LED bulbs wired to the little light in the cup holder. When I dim the gauge cluster, the LEDs dim the opposite of the cluster. For example, as the cluster gets brighter, the LEDs get dimmer, and vice versa. I tried flipping the bulbs around, which didn't change anything. Would reversing the wiring help? I don't see the difference between switching the wiring and switching the bulb, but this has me stumped!
	__________________ 298.6whp - 270ft/lbs - 8500 RPM Build Thread: http://www.clubroadster.net/vb_forum...?t=9930&page=9 Coast Works est. 2010

06-08-2010, 02:43 PM	#2 (permalink)
jnshk Member Join Date: Oct 2007 Location: Lake Jackson, TX Posts: 1,524	Re: LEDs in gauges dimming question It's been a while since I messed with the dimmer circuit, but I think you're tapped into the wiring on the wrong side of the dimmer circuit if you want to gauges to dim in synch with the dash gauges. If I remember right, the light in the cupholder area is not intended to dim with the cluster lights but rather to stay the same brightness, however the LEDs are more sensitive to changes in voltage/current which may be what gives you the unexpected dimming. If you connect to the variable illumination circuit and then directly to ground, you will notice that the dimming probably occurs in reverse (much like you are experiencing). If I recall correctly, there are three wires involved in the variable illumination circuit (a constant 12 volt, a variable voltage, and a ground?) and you need to tap into two of them at the switch (or both wires that run to the switch at one of the other variable bulbs).
	__________________ "...all the best stuff is made in Japan." Marty McFly, Back to the Future III Chaste White 1997 NA. My other car is a Ford V6 powered 1958 Volvo moneypit... err, PV444.

06-08-2010, 10:21 PM	#3 (permalink)
mighty mouse Member Join Date: Jun 2007 Location: NH Posts: 1,647	Re: LEDs in gauges dimming question ok that makes sense to me. Thanks for the input!
	__________________ 298.6whp - 270ft/lbs - 8500 RPM Build Thread: http://www.clubroadster.net/vb_forum...?t=9930&page=9 Coast Works est. 2010

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