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2013 Outback Ltd 2.5 w/ moon light
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Not an EE, but regarding the chatter from the PWM signal, wouldn't a RC low pass filter like the one described here solve that problem?
Response time does not seem important for this application, since the encoded voltage changes in one direction only during dimming.
 

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2011 OB 2.5i Prem CVT HK/AWP, Ruby Red Pearl
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Not specific to Sub/OB, these new int lighting get their pos/neg events from the BCM (easily a $500 part). I can’t see exactly how you’re interfacing these relays, but it’s apparent they’re incompatible – remove them.
On my Mazda3, I tapped from the BCM connector for the dome to my footwell leds. I used those strip 3-head cool white leds (my dome/map is cool white), no other relays/pcb/devices in the mix, and the footwells behave exactly (remote/door/on) what the map/dome does.
 

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2013 Outback 2.5i CVT Limited, Nav+EyeSight
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228 Posts
Not an EE, but regarding the chatter from the PWM signal, wouldn't a RC low pass filter like the one described here solve that problem?
Response time does not seem important for this application, since the encoded voltage changes in one direction only during dimming.
That also looks like it will work. You'll end up with a relay that clicks on or off at some point in the middle of the dim cycle (wherever the output of the low-pass happens to cross the threshold voltage for the relay).

Reason I'm hesitant to suggest something like that is the possibility of backfeed. When the PWM signal goes high, the capacitor charges through the resistor. When the PWM signal goes low, the capacitor discharges. It discharges through the relay (if it's enough to turn it on), but it ALSO will discharge back through the resistor to the source of the PWM (the BCM). At the very least you need some isolation between the two to prevent that. Maybe just a diode is enough.

Using PWM to control a light is actually pretty nice. Instead of having to drop voltage as heat somewhere and drive a bulb with < 12V, you switch it on and off to get a nice clean dimming effect. it's how they designed the stock lights to work, why not take advantage of it? There's no harm in switching an LED on and off rapidly, and it will look really nice.

Not specific to Sub/OB, these new int lighting get their pos/neg events from the BCM (easily a $500 part). I can’t see exactly how you’re interfacing these relays, but it’s apparent they’re incompatible – remove them.
On my Mazda3, I tapped from the BCM connector for the dome to my footwell leds. I used those strip 3-head cool white leds (my dome/map is cool white), no other relays/pcb/devices in the mix, and the footwells behave exactly (remote/door/on) what the map/dome does.


The way you're wiring your lights involves drawing the extra power from the existing lighting circuit. The downsides to that are:
1). Extra power draw. The power you pull for those LEDs is coming off an existing circuit. If you pull more than it was designed to pull, it will hopefully just burn out a fuse, but could also burn out a wire. LEDs draw very little power, though, so you're probably ok.
2). Isolation. When you attach things to a car with a relay, there's a mechanical disconnect between your mods and the stock wiring. If you screw everything up royally, there's still a very low chance that it will ruin any stock components. When wired directly in, you don't get that isolation.

There are also some pro reasons. For some cars (like the subaru), the wiring is actually MEANT to power additional lighting. It has the extra power capability already ready to go. I would still add an extra fuse just to be sure, but it's reasonably safe. It's also certainly a much simpler and cleaner install that way.
 

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2011 OB 2.5i Prem CVT HK/AWP, Ruby Red Pearl
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Agreed. Isolation is always best, and awareness of overloading (you can't tap fog leds from the dome).
There's also reliability (clean installs), no splice-taps (Scotchlok).
 

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2011 Outback 3.6R Limited, Red
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578 Posts
Discussion Starter #25
I've dropped the relays. I'll just run the interior lights off of the dedicated interior light circuit provided to me by subaru! Don't want to risk ruining the BCM just to have the red LEDs turn on with the domes/puddles. Maybe in the future I'll add some dedicated LEDs to the footwells that come on with the dome lights.
 

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2011 Outback 3.6R Limited, Red
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578 Posts
Discussion Starter #26
Polished up the diffuser and the light dispersal is much better. Not as good as the OEM one, but it looks good I think. If I had been more careful heating/molding the rod I think I could have polished it better. It's a pretty difficult shape to get crystal clear. Will post a picture shortly.

 

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2010 Outback 2.5
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174 Posts
How do you change the cup-holder lights? My car has transperent ring in them. I was thinking that there should be some lights there.
 

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2011 Outback 3.6R Limited, Red
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578 Posts
Discussion Starter #28
The 2010s came with the light diffuser ring already installed (lucky!). If you just want to add lights to the cup holder all you need to do is search the forums.
I searched with "cup holder illumination" and got this thread:

http://www.subaruoutback.org/forums/104-gen-4-2010-present/22006-cup-holder-illumination.html

Exactly what you're looking for. After tearing my dash area apart a couple times I can say that just doing that would probably take me 15 minutes. Make sure you get LEDs with the resistor already soldered on if you aren't able to solder. There are some links in my first post to superbrightLEDs, you can order exactly what you need.
 
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