Quote:
Originally Posted by Acree
The G/W wire runs at 4.1v no matter if the car is running or stopped.
The yellow wire goes from 0v at full brightness to ~3.8v at full dim. That's right, it's reversed. I'll have to look at this more closely tomorrow to figure out the simplest way to interface this dimming signal with your gauge.
-Acree
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There isn't a good way to get a 0-12v with the newer Subarus which are PWM for most dimming. The older models used a 12v hot side (Ill+) and then a floating ground which was 0-12v (Ill-) which controlled the dimming. With the PWM models the Ill- (the B/W wire in your diagram) is a ground while the Ill+ is still +12v all the time. With the old models you could use a simple circuit to output a 0-12v signal for gauges to use.
Probably the easiest way to control dimming is use some kind of potentiometer unfortunately. Or build something to convert the PWM to an analog 0-12v signal...
Those wires you are looking at go to the gauge cluster directly I believe to control lights which are not LEDs? So they use the old method where they are 4.1v hot all the time on one side and reversed 0-3.8v based on the dimmer switch. Just my guess.