Welcome to the North American Subaru Impreza Owners Club Wednesday March 29, 2017
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Normally Aspirated Powertrain

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 01-14-2017, 10:42 PM   #1
mcdefender
Scooby Newbie
 
Member#: 426999
Join Date: Jul 2015
Location: North Hollywood, CA
Vehicle:
2007 Impreza 2.5i
Black

Default Both headlights burn out. Twice

Impreza 2007 2.5i. I replaced both battery and alternator in 7/16. Driving on highway and ABS, emergency brake, and battery light come on and blink on and off intermitently, headlights start dimming and then go off. All other lights and car functions normally. Get home, check fuses all fine, have autozone check battery and alternator, full output/no issues. Find both headlight bulbs blown. Replace with new bulbs. 1 week later exact same thing happens. Could be the battery cables/terminals have corrosion, will try and clean up/ replace tonight. Any other explanations? I've seen other posts talking about bad ground wires, but I'm not sure how to check this. I can't keep buying bulbs and driving home in the dark weekly!
* Registered users of the site do not see these ads.
mcdefender is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 01-15-2017, 07:41 AM   #2
Daniel Dudley
Scooby Specialist
 
Member#: 307610
Join Date: Jan 2012
Location: Far Out
Vehicle:
2004 WRX Wagon

Default

Take back the alternator and get another one.
Daniel Dudley is offline   Reply With Quote
Old 01-15-2017, 12:04 PM   #3
mcdefender
Scooby Newbie
 
Member#: 426999
Join Date: Jul 2015
Location: North Hollywood, CA
Vehicle:
2007 Impreza 2.5i
Black

Default

Quote:
Originally Posted by Daniel Dudley View Post
Take back the alternator and get another one.
Really? How would I know the alternator is the problem? I've seen lots of people comment that refurb alt can be doa, but it seemed to be fine for last 6 months..
mcdefender is offline   Reply With Quote
Old 01-15-2017, 01:13 PM   #4
Charlie-III
Scooby Specialist
 
Member#: 30669
Join Date: Dec 2002
Chapter/Region: Tri-State
Location: USA, North NJ, 07456
Vehicle:
1998 Legacy 2.5GT
Silver Sleeper Wagon

Default

Quote:
Originally Posted by Daniel Dudley View Post
Take back the alternator and get another one.
Why?

Granted, maybe the voltage regulator is bad so the voltage wanders, or a diode is failing so the system sees AC voltage (although bulbs shouldn't care).
Just curious why you stated to replace without any ideas or thoughts posted.
Charlie-III is offline   Reply With Quote
Old 01-16-2017, 05:50 PM   #5
v2rocket_aka944
Scooby Newbie
 
Member#: 408701
Join Date: Dec 2014
Default

bulbs blow from physical damage, too much heat (current), or too much voltage.
they tend not to blow at the same time though!

i would check your running voltage at the battery and at the alternator terminal, relative to ground. you might be putting out (at least occasionally) a higher than normal voltage due to faulty regulator as mentioned by Charlie.

most of the stuff in a car's "12 volt" system is good to 15 VDC or so but its possible for an alternator to put out more than that.
v2rocket_aka944 is offline   Reply With Quote
Old 01-16-2017, 09:38 PM   #6
Patrick Olsen
NASIOC Supporter
 
Member#: 120
Join Date: Jul 1999
Chapter/Region: AKIC
Location: Where the Navy sends me...
Vehicle:
1997 Legacy 2.5GT
1996 Impreza coupe

Default

Have you cleaned the MAF? When was the last time the timing belt was changed? Is it tripping any CEL codes?
Patrick Olsen is offline   Reply With Quote
Old 01-16-2017, 10:48 PM   #7
pho_shizzle
Scooby Specialist
 
Member#: 181064
Join Date: May 2008
Chapter/Region: BAIC
Location: Bay Area
Vehicle:
00' 2.5RS
BRP

Default

Just out of curiosity and for the record. Are you running factory halogen bulbs?
pho_shizzle is offline   Reply With Quote
Old 01-18-2017, 10:23 PM   #8
mcdefender
Scooby Newbie
 
Member#: 426999
Join Date: Jul 2015
Location: North Hollywood, CA
Vehicle:
2007 Impreza 2.5i
Black

Default

Hey guys, appreciate the input on this thread. Yes, factory halogen bulbs, timing belt changed approximately 15k miles ago, and didn't check the MAF since no CEL codes being tripped.

Removed the alternator and had autozone bench test it today, looks like it was a bad rebuild. Got it swapped out under full warranty, hopefully that solves it!

Thanks again.
mcdefender is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -4. The time now is 07:20 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2017 Axivo Inc.
Copyright ©1999 - 2017, North American Subaru Impreza Owners Club, Inc.