Subaru Outback Forums banner

1 - 15 of 15 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
I've got my daughter"s 2002 Outback home from school. Apparently for quite some time the battery and brake warning lights on the dash will flicker quickly a couple times at the same time. At night the headlamps seem to flash brighter when it does this. It's only done it a couple times for me and it seems like they briefly get brighter and not dimmer when the dash indicator lights flash but it happens so fast that it's hard to nail it down. It may only do it once or twice or not at all per drive so it's hard to get more information.

She's been driving it for at least a year with it doing this (I know). I've been driving it for a couple weeks to work to watch it and I've only seen it about three times.

Any ideas???

Thanks
 

·
Premium Member
2010 Legacy 3.6R Limited
Joined
·
1,300 Posts
Sounds like the same stuff I'm going through with my alternator. How old's the alt? What kinda shape is the battery in? Connections on all of the above tight and in good shape?


The charge MIL (battery light) will trip the brake indicator to disable the daytime running lights when there's a charging issue to preserve power.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #3
I don’t know the age of the alternator. The battery is a couple years old. Ive cleaned the battery terminals and the stud on the alternator. Guess I should check all the grounds too. I’ve been suspicious of the alternator but couldn’t figure out the brake light. Now I see how they’re connected. I’ve thought of connecting a voltmeter to check but it happens so fast and then doesn’t repeat.
 

·
Premium Member
2010 Legacy 3.6R Limited
Joined
·
1,300 Posts
Yeah, I've even just learned about the technicals on how the charge light/brake light relate to the alternator function itself, but basically the alternator and the battery aren't agreeing on something, and that's when the light comes on/flickers.


Before we get any farther, what engine/model is that car, is it a 2.5L base/limited or is it H6-3.0 LL Bean/VDC? The alternators function differently. You can also add this information into your profile so we eventually stop asking.
 

·
Premium Member
03 H6 OBW & 06 WRX Sportwagon
Joined
·
17,814 Posts
is it a 3.0 ? some folks have been sold incorrect replacement alternators, the one for the 2.5
 

·
Registered
2017 Outback 3.6 Touring, which replaced '05 Outback XT
Joined
·
800 Posts
From the description of the lights going bright, I'd be worried about an over voltage condition possibly damaging electronics like the ECU. The cause could be a bad regulator in the alternator. Time for a factory rebuilt.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #7
Yes, it's a 2.5 with auto trans

I haven't been driving it and decided to take a look before going out and picking up an alternator. I warmed it us just now and checked the voltage.

At idle- 13.97-14.03
At idle the cooling fans kicked on and it flashed down to 13.5 for a brief moment and then recovered to 14.02 steady. Fans turned off and it stayed around 14.02
I brought up the RPMs and the voltage came up to 14.1
I run it there until the fans kicked on again and the voltage was rock steady at 14.1
I brought the RPMs back down to idle and was standing there scratching my head watching the meter when it jumped up to 15.5 and then 16 so I shut it down.

I gather the voltage is regulated internally on these alternators? My daily driver is a '70 Dodge Swinger I restored and it has an external voltage regulator mounted on the firewall. It's a rolling hobby throw-back to my youth that I do all the work on myself. None of our newer cars have ever had any alternator or voltage problems while we've owned them so I'm not as familiar with electrical systems newer than 40 years old. Wow, I'm feeling old all of a sudden...

Anyway- it looks like a replacement alternator is indeed in order unless anybody has any other comments or suggestions. BTW- what should be the normal output voltage range on one of these alternators? I'm used to the 14.3-.5 range of the antiques I work on.

Thanks a lot for all the suggestions. I do appreciate it.
 

·
Registered
Joined
·
18,408 Posts
As has been mentioned, the symptoms of the warning lights flickering on and the headlights brightening momentarily are consistent with the system voltage going high, i.e., not being properly regulated.

The internal regulator in the alternator might be failing. But also, the regulator monitors the system voltage through a connection back to the battery. If that sensing voltage is lost (e.g., disconnected), the alternator output will increase, although it should still be held to a safe level.

The sensing voltage comes through a fuse in the main fuse box. If there's a bad connection at the fuse it could cause the same effects. The fuse is identified on page 12-12 of the Owners Manual as #3, 10 Amps.

Remove the fuse (ignition Off) to check the contacts, or perhaps just replace it. Might be lucky . . .

Also, the sensing voltage comes to the alternator 3-contact connector at the middle contact. Again, an intermittent connection there could lead to the same symptoms. There have been cases where the plastic of the connector has become brittle, or even broken apart leaving the wire connections loose. The contacts can also be corroded and intermittent.

Note, there's full battery voltage on the #1 and the middle, sense, contact wires at all times -- disconnecting the battery might be a good approach.
 

·
Registered
Joined
·
46 Posts
I agree with the above posts. On my '02, I went through 2 alternators in my 65k miles of driving it. I'd recommend changing it yourself, if it is the issue. Super easy. But are sure the belt isn't too tight, as I'm guessing that's what made my second one wear out.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #10
Yes, it's a 2.5 with auto trans

I haven't been driving it and decided to take a look before going out and picking up an alternator. I warmed it us just now and checked the voltage.

At idle- 13.97-14.03
At idle the cooling fans kicked on and it flashed down to 13.5 for a brief moment and then recovered to 14.02 steady. Fans turned off and it stayed around 14.02
I brought up the RPMs and the voltage came up to 14.1
I run it there until the fans kicked on again and the voltage was rock steady at 14.1
I brought the RPMs back down to idle and was standing there scratching my head watching the meter when it jumped up to 15.5 and then 16 so I shut it down.

I gather the voltage is regulated internally on these alternators? My daily driver is a '70 Dodge Swinger I restored and it has an external voltage regulator mounted on the firewall. It's a rolling hobby throw-back to my youth that I do all the work on myself. None of our newer cars have ever had any alternator or voltage problems while we've owned them so I'm not as familiar with electrical systems newer than 40 years old. Wow, I'm feeling old all of a sudden...

Anyway- it looks like a replacement alternator is indeed in order unless anybody has any other comments or suggestions. BTW- what should be the normal output voltage range on one of these alternators? I'm used to the 14.3-.5 range of the antiques I work on.

Thanks a lot for all the suggestions. I do appreciate it.
 

·
Registered
subaru wagon outback 97, 2.5ltr non turbo
Joined
·
3 Posts
flickering dash and headlights/alternator

from subaru97man Im having the same similar problem with all the dash lights flickering and the headlights as well some times it does it and only a short time it stops and then starts doing it all over again. its a headache at night. Also i can hear a winning noise comming from the alternator, softer when in park and a bit louder when in drive, voltage shows 14v plus or minus a bit. batterys ok terminals are clean. Im stumped if the regulator is faulty it should show no voltage i think, maybe brushes are worn, did you figure it out yet with yours? if so was it the alternator or something else?
 

·
Registered
Joined
·
6 Posts
Discussion Starter #14
The old alternator didn't make any noise. It was just voltage increases. They were random as after checking the voltage under varying conditions, I was about to disconnect the voltmeter and close the hood when I saw it jump up to 16 volts. A new alternator for an auto transmission Outback sourced local for me was $170.00. I'm thinking I'm going to thin the herd and sell this car so I hedged my bets and picked up a used one at our local Pick-N-Pull salvage yard. They were having a half-off-any-part weekend special so I took a chance and paid $17. These Subaru alternators take only about ten minutes to change out. It works beautifully. At first I kept telling myself that it was my imagination that the idle was smoother but now I can honestly say it is. It would have tiny little fluctuations which were noticeable while stopped at traffic lights. Now the idle is rock steady.

No more flickering dash lights and no more fluctuating headlamp brightness.
 

·
Registered
'15 Outback 2.5i Premium
Joined
·
2,531 Posts
Thanks for letting us know your solution. Glad it worked!
 
1 - 15 of 15 Posts
Top