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Dual filament tail-light...what???

PostPosted: Fri Feb 15, 2013 12:02 am
by jakey
G'day,

So after testing for like an hour and having no luck on facebook I have come to consult the boards.

What is the dual filament in the tail lights for? Car is a my06 Preface.

I can get 1 filament to come on with the front lights (so these are tail lights?) but what does the other filament do? my instinct was that it would be for brakes, but they do not trigger it to come on.

Any ideas? Surely someone has noticed they do nothing before - what could I be missing? Fuse (for what)?

Re: Dual filament tail-light...what???

PostPosted: Fri Feb 15, 2013 2:05 am
by zch91
Are there 3 wires going into the bulb socket? Probably just Subaru being retarded and not giving us audm guys some of the simple JDM shit.. It's happened before.

Re: Dual filament tail-light...what???

PostPosted: Fri Feb 15, 2013 12:08 pm
by jakey
As you can see in the picture, I'm led to believe maybe it is for brakes and both of my filaments are blown? Not sure why else?

It's hard to tell exactly where each wire goes, but I tried to look close, a lot of the wires are taped together. I could be wrong.

The black and red go into the socket connector, but the white one goes via the brake lights first?

Re: Dual filament tail-light...what???

PostPosted: Fri Feb 15, 2013 2:52 pm
by Surge
Yeah I would say its for the brake lights.

Maybe blown or maybe just take one out and refit it, one of mine was just loose once and after refitting it worked fine.

Re: Dual filament tail-light...what???

PostPosted: Fri Feb 15, 2013 4:17 pm
by jakey
Surge wrote:Yeah I would say its for the brake lights.

Maybe blown or maybe just take one out and refit it, one of mine was just loose once and after refitting it worked fine.



Yeah I've tried that a few times.

I have ordered some dual filament t20's from the US they are due here today hopefully or early next week. I will fit and see if I get an new lights :)

Re: Dual filament tail-light...what???

PostPosted: Fri Feb 15, 2013 5:28 pm
by paggaz
I doubt you'll get any extra lighting from replacing the bulbs.

I'm with Zach on this one. It's some fancy JDM option for rear fog lights, but skimped out on the wiring for AUDM models.

I've utilised the dual filament bulb in an SG Forester before, wiring the extra filament as a brake light, so when brakes are applied you get four lights lighting up (rather than just two), with the dual filament being as bright as, if not brighter, than the stock brake lamp.

Re: Dual filament tail-light...what???

PostPosted: Fri Feb 15, 2013 5:56 pm
by jakey
paggaz wrote:I doubt you'll get any extra lighting from replacing the bulbs.

I'm with Zach on this one. It's some fancy JDM option for rear fog lights, but skimped out on the wiring for AUDM models.

I've utilised the dual filament bulb in an SG Forester before, wiring the extra filament as a brake light, so when brakes are applied you get four lights lighting up (rather than just two), with the dual filament being as bright as, if not brighter, than the stock brake lamp.


That's the thing, afa i can see it's wired in to the brakes, so if it doesn't come on when I replace it I will double check it is wired correctly and go from there. Would be great to have as extra brake light.

Re: Dual filament tail-light...what???

PostPosted: Fri Feb 15, 2013 5:57 pm
by champ
one filament is the tail-light (the dimmer one), second filament is for the brake lights.

Re: Dual filament tail-light...what???

PostPosted: Sat Feb 16, 2013 8:16 am
by dr20t
The dual filament also acts as a fail safe for another circuit in the car relating to the ecu - I can't remember what exactly and will have to dig it up but I remember when I blew both filaments my car wouldn't idle properly - I *think* its on the same circuit as the maf sensor / Crank angle sensor