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Old 08-09-2011, 05:16 AM   #1
Scooby Specialist
Member#: 161701
Join Date: Oct 2007
Chapter/Region: VIC
40 iTS U-R-A-BUS

Question Headlights turn on by themselves (while car is off), how to troubleshoot?

Calling all electronic and lighting gurus out there for some help, I think my car is haunted....j/k.

Anyways, first of all it is NOT the parking break light switch issue.

Car info:

04 canadian spec STI with retrofitted TSX projector low beam headlights.
(retrofit has been installed for 3 years, never has this issue occured before)

Here's what happened. It started after I washed my car yesterday in the evening (9pm-ish). I have my keys in my pocket and was in the process of drying my car, I suddenly notice that my headlights (TSX projector low beams) have turned on. Being puzzled and shocked, I get in my car to check everything (light switch at "off" position, hand brake up and KEY NOT IN IGNITION) I then start the car toggle, the switch on and off, released and engaged the hand brake a few times and then the lights go off. I finish up drying the car, clean up and then arm the car alarm and get back inside the house.

My mom then wakes me up at 3 in the morning telling me that my car lights are on. Once again my keys are on my table, so I go out and do the same things I did earlier and managed to turn off the lights. Low and behold, the next morning my car wouldn't start because the battery was almost completely drained from the projectors being on for about 2 hours (My brother returned home at 1am and my car's headlights weren't on, therefore it must've turned on by itself between 1am and 3am).

I jump start my car and head off to work, after getting to work, I made sure the lights were off before I went in. I parked in a spot where I can see my car whenever I walk by the receiving doors of the place I work at. Throughout the day when I passed by the doors, I would check my car and it would be perfectly fine. At least I thought it was.

I got off work at 9pm and then walked to my car, as I got within visual range, I saw the lights on AGAIN.

I've searched well over 20 threads where majority of them are about lights not being able to turn on, but was only able to find one thread with a similar problem:


Unfortunately a resolution was never posted. I've currently pulled out the fuse that is near the relay kit for the lights hoping that the lights won't auto turn on. If anyone can help, please chime in, if you don't have any helpful things to say, please do not post.

Thank you in advance, your help is much appreciated!w
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Old 08-09-2011, 06:50 AM   #2
Scooby Newbie
Member#: 274613
Join Date: Feb 2011
Chapter/Region: E. Canada
Location: Ontario, Canada
2015 WRX


Definitely haunted.

If you've modified the stock wiring, then it'll be more difficult to diagnose.
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Old 08-09-2011, 07:59 AM   #3
Scooby Specialist
Member#: 284753
Join Date: Jun 2011
Chapter/Region: Tri-State
Location: Colonie, NY
2004 WRX STI
World Rally Blue


I would start by pulling the relay and testing to see if you have constant power at the relay (while its ocurring) That will tell you if its more towards the switch or the headlight.
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Old 08-09-2011, 08:18 PM   #4
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Member#: 53443
Join Date: Jan 2004
Location: Anchorage, AK
2001 LL Bean Outback


Usually the headlight circuit requires that both the ignition switch and the headlight switch be turned on in order to for the lights to work. Your lights must have been modified in order for this trouble to occur. Normally the light switch supplies a ground connection for the lights and the ignition switch supplies power to the relays which are also controlled by the light switch. Check to see if power is getting to the low beam lights even though they are off. If you do have power there this would mean there is something going on with the ground connection. There may be a problem with the light switch also.
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Old 08-09-2011, 08:35 PM   #5
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Member#: 123245
Join Date: Aug 2006
Chapter/Region: Tri-State
Location: york,PA
2002 wrx


I had an issue with one of my retrofitted sti projectors flickering after shutting off the car. Turns out the relay in the aftermarket wiring was full of water. Might want to check that if you have it.
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Old 11-17-2011, 05:20 PM   #6
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Member#: 161701
Join Date: Oct 2007
Chapter/Region: VIC
40 iTS U-R-A-BUS


Sorry for not responding my solution to this, completely forgot about this thread until I was looking at my thread start history.

Anyways, like most people have stated, the problem was the relay getting wet. I swapped in a new one and the problem is gone.

Cheers and thanks again for all the responses.
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Old 11-17-2011, 07:32 PM   #7
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Member#: 225024
Join Date: Sep 2009
Location: San Diego, CA, USA, Earth, ...
2002 wrx


yup, i had the same problem with the same solution a few days ago (and started a thread in this sub-forum)...new relay from radioshack: $5

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