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Discussion Starter · #1 ·
I really only notice this when I'm parking, but when I turn the steering wheel the headlights dim a little and the fan for the heater weakens. Once I stop turning the wheel, they jump back to full intensity. Does anyone else notice this (I have a Premium)? Would replacing the wiring from the battery to a lower gauge (i.e. Big 4 replacement) help? Thanks!


I'll see if I can get a video of it to post.
 

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I'd potentially take it in if it's noticeable and easily reproducible. What you are describing makes it seem like the alternator isn't making enough amps/volts at low rpm and so when you steer at low speeds the steering system has to work harder and you're seeing a voltage/amperage drop which is causing the lights to dim.
Any long starts or anything?
 

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Discussion Starter · #3 ·
Any long starts or anything?
No, not even in sub freezing temperatures. Although come to think of it, on the really cold days I remote start with the app, which is probably 90% of the time, so I actually have no idea... I'll investigate.
 

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I am in a touring and have not seen this as of yet. I will check next time I have the opportunity. Sounds like the power steering is using a decent amount of power to move the wheels when rpm's are low.
 

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Totally different headlights...

I am in a touring and have not seen this as of yet. I will check next time I have the opportunity. Sounds like the power steering is using a decent amount of power to move the wheels when rpm's are low.
His headlights are fixed halogens, while yours are LED Projectors with steering motors. Your results will be quite different.
 

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Sounds like the battery is getting weak or the electric power steering is drawing too many amps. Dealer should be able to figure it out easy enough and fix it.
 

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Discussion Starter · #7 ·
... it seem like the alternator isn't making enough amps/volts at low rpm...
I think you're on to something. I tried revving the engine in neutral and the problem went away; dropped the rpms to idling and the dimming came back. Just a side note, the interior lights dim as well, but the screen of the infotainment system does not.
 

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I think you're on to something. I tried revving the engine in neutral and the problem went away; dropped the rpms to idling and the dimming came back. Just a side note, the interior lights dim as well, but the screen of the infotainment system does not.
The lights are directly connected in some fashion to the electrical system while the head unit may either have a capacitor or step down to a lower voltage or both. If you can easily replicate the problem I'd take it in.
 

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I had a 2008 Honda Accord, on which the headlights dimmed at idle. It bugged me to death. Combined with the excessive road noise, I sold that vehicle in less than a year. There was no solution and many Accord 4-cyl owners experienced the very same thing. My vote is on the alternator.
 

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Discussion Starter · #10 ·
Ok, so I finally brought it back to the dealer. I'll note that I only noticed this issue because where I park I back into the spot where I need to come to a complete stop and turn my wheels. My headlights shine on a large wall about 20 meters away while I'm doing this.

This was the first anyone at the dealership had heard of this issue... great. The tech almost didn't believe me until I showed him video of it.

About an hour later I get a call. To quote them almost exactly "we're gonna have to keep it a few days, it definitely does it and nobody has any clue why." Oh boy! They couldn't replicate it on another Ascent. They even called Subaru's technician help center, who had no idea either.

They gave me a 2019 Outback Premium loaner for the next couple of days (side note, if I didn't get the Ascent I absolutely would have gotten an Outback). So I drive it home, back into my spot, and wouldn't you know: THE OUTBACK DOES THE EXACT SAME THING! The headlights dim when I turn the wheel at low RPM.

I get a call from the dealer first thing in the morning. Apparently they tested the headlights the day before on a Touring, not Premium. They tried a Premium that morning and that Ascent had the dimming lights at idle. Essentially there's nothing they can do about it right now, but they did open a ticket with Subaru to see if its something they can look into in the future.


TL/DR: Dimming headlights at idle is just something that happens with the Premiums.
 

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Yes, my Ascent Touring Canada edition (equivalent of the Premium trim in the US) with Halogen headlights does the same thing when I come out of the garage backing up while steering, the lights will flicker momentarily. So you're not alone with those symptoms.

No idea why the Premium and Touring trims are reversed up here in Canada compared with the US.
 

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It's not uncommon for this to happen. At idle if you put an amperage draw on the system, you will notice a dip. Your headlights will dim, the ac fan will sound like it's under a load, etc. The steering system is electric assist and you have to account for the demand you are putting on it by turning the wheel while not moving. It's a really big force. If you have ever tried turning a steering rack by hand at the wheels, you'd know how hard it is to do, and that's not accounting for the weight of the front end on the steering system. LED headlights wont show this difference because the "dip" wont be lower than the forward voltage the led needs to stay illuminated. But halogen/ incandescent bulbs are basically resistors that are also indicators (brightness or lack of) indicate load on a system.

Some old elevator controllers actually used light bulbs for this very purpose.
 
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