09 headlights at random on & off

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Woodchuck
Posts: 1
Joined: Thu Sep 03, 2015 8:43 pm

09 headlights at random on & off

Unread post by Woodchuck » Thu Sep 03, 2015 8:56 pm

    I have a 2009 Buick LaCrosse CX 3.8 . What i have is that the headlights turn on and off by them self at random . Not running parked nobody around. Can use some help on this one . Thanks Chuck

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    carriedi
    Posts: 2500
    Joined: Wed Apr 10, 2013 12:42 pm
    Location: Oregon

    Re: 09 headlights at random on & off

    Unread post by carriedi » Fri Sep 04, 2015 3:55 am

    you're going to have to check it when it's acting up. there is a relay called the HDM relay #35 in the underhood fuse box. you're have to check to see if the BCM is sending out the signal to turn on the relay or the relay is turning on the light by itself.

    the headlight switch, the BCM or the HDM relay need to be checked when the headlights are on by themselves.

    scan for codes
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    Dexterwise
    Posts: 7
    Joined: Sun Sep 13, 2015 3:51 pm

    Re: 09 headlights at random on & off

    Unread post by Dexterwise » Sun Sep 13, 2015 4:46 pm

    Chk all fuses in the hood, batterterminal connections for looseness, and chk if the connctors are weak.

    Ironworks25
    Posts: 4
    Joined: Wed Jan 12, 2022 3:38 pm

    Re: 09 headlights at random on & off

    Unread post by Ironworks25 » Wed Jan 12, 2022 6:35 pm

    Did you ever sort out the problem or better yet the solution. I know this is a very old post. But I have the same issue in 2006 Pontiac Grand Prix GT. Switch is good, I don’t know if we have issue with BCM. Sounds if I should be checking into a possible bad relay next.

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    carriedi
    Posts: 2500
    Joined: Wed Apr 10, 2013 12:42 pm
    Location: Oregon

    Re: 09 headlights at random on & off

    Unread post by carriedi » Thu Jan 13, 2022 1:54 am

    The person never got back to let us know what the fix was. The BCM is a common failure with the headlight coming on by themselves. Just check the HDM module (relay 35) maybe switch it with another relay of the same type and see if it still happens. If it does then you are probably looking for a BCM.

    Or like I said in your other post, just yank the HDM when you park your car. This will keep your headlights from coming on and will disconnect the relay circuit from the BCM so it won't drain your battery