Headlights turn on when car is off

[hormy83]

Yesterday morning I went to take the car out and it wouldn't start. I jumped it, got it to start, and figured it may be about the end of the battery's life. Then later in the day I took it to the Auto Parts store and had the battery tested and it came out fine. So then I thought maybe I had left a light on or maybe hit the start button one extra time when I shut it off and left the accessories on. Well I parked it in the garage last night, made sure it was completely off and went into the house. A few hours later I had to go into the garage to get something, and I noticed my headlights and taillights were on. I am positive they were off after parking it - I had the headlight dial in the auto position.

I then went into the car and turned the headlights to the off position and didn't notice an issue again, and this morning it started fine. Any great ideas on where to start on troubleshooting this? I am considering when I have the car out during the day and am at work I will leave the headlights in the off position - but at night in the garage I will have it in the auto position to see if it does it again. That way if it does I'm at least at home and it is easier and less of a headache to jump.

It is a 2008 M35x.

[Rogue One]

I think this might help you.

Check the headlight / turn signal stalk. That has a bunch of metal strips and contacts that can become corroded. It comes off the steering column with 2 bolts and a couple of easy plugs.

Sorry for the non-NICO link!!!:
http://www.sr20-forum.com/interior-exte ... nswer.html

[The00Dustin]

I think the real question is should the headlights ever come on when the car is off? I know they turn off when I open and shut the door or after a certain amount of time when I have them on auto and turn the car off, but I almost always have them in the off position because I don't like where the auto position is and I don't like that the auto can't control the dash separately (IE, I turn on headlights, but it is bright out, so dash stays in day mode). Since I mostly don't use the auto (except as an on because of its stupid position), I can't say how they are supposed to work. That having been said, if you can figure out a way to make the lights come on when the car is not running, you can find yourself a potentially suspect component. For instance, if the headlights should come on when you open the door, then I would think the door switches would be suspect. I mention this because that would be easier to deal with than the headlight MFS ("stalk" mentioned in Rogue One's quote). I didn't follow that link, but I will say this: I personally wouldn't have thought to suspect the headlight MFS could be related, but that's because I automatically assume it drives a relay. In reality, as can be seen in the FSM, the headlight MFS uses multiple contacts to send a digital signal somewhere, and in some cases, multiple contacts are engaged. If multiple contacts are supposed to be engaged, then the digital signal would mean something else if one of the contacts turned off due to corrosion and another didn't. If that is the problem, unless the off position turns off all relevant contacts, even it isn't guaranteed safe. Yikes, and good luck.

[hormy83]

Thanks for the thoughts and link. I have been continuing to pay attention and see if I could get it to do it again and I haven't had any other problems. If it happens again I will check the door switches to see if something is up with those and if that isn't it I will tear into the headlight stalk.

[mambaocho]

The same thing happened to my m37 a few weeks ago but the battery wouldn't charge. Took it to the dealership and they found a short in right headlight module which drained and killed the battery completely. Looking at the work order, the parts replaced are the battery and headlight control unit (xenon-28474-8992A). I haven't had the issue since. Hope that helps.