[03' Pontiac] Headlights turning on at night, and ECU-B?

Stereo, security systems, vehicle electronics, and electrical-related discussions
KyleOckerlund
Posts: 3
Joined: Fri Dec 29, 2017 11:34 am

[03' Pontiac] Headlights turning on at night, and ECU-B?

Postby KyleOckerlund » Tue Jan 02, 2018 1:46 pm

Good afternoon,

2003 Pontiac Vibe owner here, and I've been having a problem with the headlights recently. They just kinda... turn on. In the middle of the night. I'll wake up to glaring headlights and a dead battery, even though they were off the night before. I'm thinking it may be temperature, it has hit -10 by me recently.

I was thinking it may be an issue with the DRL sensor, so I went in and pulled the ECU-B fuse (see attached for the manual picture) for the DRL. After doing that, Nothing changed. I checked to be sure it was the right fuse 132 times, but everything was still on and running, DRL included. I have no clue what it did, so I put the fuse back in case it was an airbag or something. I've read plenty about the DRLs on here too, and I'd try other things, but in this weather I'm not about to go cutting wires if I don't have too. Rather, I don't want to be fixing any mess ups in this weather, but you get the idea :lol:

So... any idea about the headlights? Also, side note, what does that ECU-B really do?
Thanks gang,
~Kyle
Attachments
vibeFuses.png
2003 Pontiac Vibe Fuse diagram
vibeFuses.png (124.38 KiB) Viewed 422 times

User avatar
joatmon
Posts: 9086
Joined: Fri Mar 21, 2003 5:19 am
Location: SMC MD

Re: [03' Pontiac] Headlights turning on at night, and ECU-B?

Postby joatmon » Tue Jan 02, 2018 2:28 pm

Welcome to genvibe

Check out viewtopic.php?t=35276 , see if going hi beams works in the short term.

KyleOckerlund
Posts: 3
Joined: Fri Dec 29, 2017 11:34 am

Re: [03' Pontiac] Headlights turning on at night, and ECU-B?

Postby KyleOckerlund » Tue Jan 02, 2018 7:25 pm

I'll give it a try, thanks!

In the meantime, ECU-B anyone?
~Kyle

jolt
Posts: 580
Joined: Sun Mar 02, 2014 2:07 am

Re: [03' Pontiac] Headlights turning on at night, and ECU-B?

Postby jolt » Wed Jan 03, 2018 1:21 am

By the wiring schematic, the headlights are controlled by "Daytime Running Light Relay" or controller. This controller is powered by the "ECU-B" fuse and the fuse labeled "GAUGE". So the controller relay has two power sources. You could also pull the "Head Light Main" 40 amp fuse to prevent the headlights from coming on but the relays would still be powering up.

I would have suspected this control relay as a possible source of the problem except for the know problem of the headlight combination switch that was pointed out by joatmon. The switch could also be the problem as it has "Flash to Pass" where you pull back on the stock to flash the headlights. This would explain why pushing the stock to the high beam position could prevent the heads from coming on. If the switch stock pivots were worn so that the switch was making contact in the "Flash to Pass" mode or very close to making contact, the lights could randomly come on. By moving the stock to the high beam position, the contacts in the switch for "Flash to Pass" are as far away from each other as possible.

Here is a link to some switches on Ebay: https://www.ebay.com/sch/i.html?rmvSB=t ... ase%201.8L

doddthedude
Posts: 1
Joined: Fri Jan 05, 2018 5:19 am

Re: [03' Pontiac] Headlights turning on at night, and ECU-B?

Postby doddthedude » Fri Jan 05, 2018 12:29 pm

had the same problem with my 1999 Izzu Trooper.. headlights would come on when temp dropped below 30. live in Fl so not too much of a concern as it does not happen much. But for past 3 days it has been below freezing at night and woke to the headlight on. could never find cause as it was always warmer by the time I got to shop so left it overnight and was told it was the headlight switch and part alone was over 500. brother found this site and I made sure to put switch to bright before going to bed. woke up to check and headlights were off and it was 26 degrees so saved me some money

User avatar
tpollauf
Posts: 3270
Joined: Wed Jan 20, 2010 11:37 am
Location: Toledo/Oregon, Port Clinton Ohio
Contact:

Re: [03' Pontiac] Headlights turning on at night, and ECU-B?

Postby tpollauf » Fri Jan 05, 2018 1:36 pm

OK. I've been following this post and some of the symptoms you've all experienced. Two weeks ago when we experienced our first (of many) sub zero degree overnight temperatures, my son's 2009 Vibe GT had a dead battery. I mean totally dead as if there wasn't even a battery in the car! No dome light on when opening the door, no dash lights when inserting key and trying to start... nothing! So I put it on the battery charger for an hour or so, came out and started the car (no problems at all) and it's been fine for two weeks and counting. I wonder if his car experienced this exact same thing where the lights came on by themselves to where it totally drained the battery? I'll have to keep an eye on this one.
Image
"everything is modifiable"

KyleOckerlund
Posts: 3
Joined: Fri Dec 29, 2017 11:34 am

Re: [03' Pontiac] Headlights turning on at night, and ECU-B?

Postby KyleOckerlund » Sun Jan 07, 2018 9:36 pm

Yeaaa I hear that for the dead battery. When this killed my battery in the first place, I took my 2 week old battery into Pep Boys for a reading.

Rated: 640 cca.
Measured: 2 cca.

I'm still going to try the stick trick and see if that works, if it does I'll let you all know (It hasn't been too cold recently!)

And Jolt, that depth of knowledge is...impressive to say the least :o
~Kyle


Return to “Audio, Electronics, Electrical”

Who is online

Users browsing this forum: No registered users and 2 guests