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2003 forester 2.0 xt at
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698 Posts
Discussion Starter · #1 ·
I just retrofitted my forester, leaving one of the two h4 contacts un used.
I cant switch my aux light on with the signal from un used h4 contact.
Do i need a resistor or something for it?

How it was connected:
85- h4 contact (earth)
86- h4 contact (signal)
30- battery with 15 amp fuse
87- + aux
 

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2003 forester 2.0 xt at
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698 Posts
Discussion Starter · #3 ·
Tried something else:
30: + battery with fuse
87: to aux
86: + battery wirh fuse
85: signal from H4 contact.

Works fine, until i take the stalk down (there is supposed to be NO lights, the same as turning key off)
The low beam is on, and if i push the stalk, only aux lights are on.

Im getting very frustrated
 

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2006 Forester 2.5X Manual
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56 Posts
I know Subaru has a tendency for switching the ground side of a loop, not positive. So essentially positive is ALWAYS powered.

If you're having issues finding the correct trigger location, it may be you need to pick up a negative lead at a headlight, not positive.

I am not an electrical guy, and have needed help troubleshooting my own lights. That was part of the problem I was having.

Sorry I can't be more specific.
 

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2003 forester 2.0 xt at
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698 Posts
Discussion Starter · #5 ·
I know. I guess the xenon makes all the fun here. Im gonna try putting a h4 bulb in the available slot, and see if that does anything. Its basicly the signal i cant get right. I can trow a switch in the car, but its just hazzle turning it on and off :(
 

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Administrator
2016 & 2018 2.5i Premium CVT
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On the US spec SG models there is some other circuitry that runs through the headlight filaments: DRL through low beam and something associated with controlling fog lights through high beam. Either of these could be of sufficiently high resistance as not to leave enough voltage at the disconnected terminals to power your relay. Try connecting the relay across a pair of terminals that are connected to the headlight. Those terminals should see almost the full voltage.

And yes, Forester headlights are switched on the .low side up till (approximately?) the SH models. Common +, and switched low side to control which beam comes on.

Non-US model: YMMV
 

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2003 forester 2.0 xt at
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698 Posts
Discussion Starter · #7 ·
My eudm has its own foglights switch by the cruise and stuff.
I have tried the other h4 contact asswell, its all the same.
I hope putting a bulb in the available contact sorts my issue. If not, i just have to fit a switch in the car :(
 

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2016 & 2018 2.5i Premium CVT
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Yes, it's the same thing here regarding the foglight switch. The foglight involvement in the headlight circuitry appears to be one of making it so that they can only come on with low beams. It's quite obscure, but worth knowing about only in that it does involve the high beam connections and can produce unexpected situations when you mess around with them .
 
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