Ignition switch short? haunted taco?

Greetings, A couple of nights ago I looked out back and saw my headlights on. Key was in my pocket. Huh? Went out, started her up, shut her down, lights went off when I opened the door - just like normal. Half an hour later, the alarm goes off. This time, the dash lights are all on (as if the ignition was on, but engine not started), but they were all dim. Ooh, this doesn't look good. Unhooked the battery this time. Next day, tried again. Lights again came back on by themselves after half an hour or so. Inserting and then wiggling the key turned them off. It has been really wet here in Seattle, so I took off the dash panel to see if it was wet near the ignition switch. Nope, dry. So now I am wondering how best to proceed... My guess is that is a problem right in the ignition switch, not in a relay somewhere else. I think this because I was only lightly wiggling the key in the ignition when the lights went out. Is there a contact that detects when the key is in the off position? If so, and that contact is getting dirty/dusty/rusty, it seems to me that this could be the cause. Can I get into the ignition assembly and inspect and clean that contact? Any advice/gotchas on removing that assembly? (It looks easy enough.) If I cannot clean, do I have to replace the entire ignition switch assembly? That looks expensive. After that, do I have to rekey? Or can I swap out the lock cylinder and keep my existing keys? Any help, advice, pointers much appreciated Cheers, Chris.

 

Unless you're in the (bad) habit of leaving your headlight switch in the 'on' position all the time (relying on the light auto-off function), it's probably not the ignition switch.

 

Thanks EnolaGaia.

I drive with lights on even during the day, so yes I do leave the headlight switch on all the time. Why is this bad? Why should I not rely on the headlight auto-off feature?

While this headlight switch question is an interesting discussion, I think the primary question still remains... (I should have made this clear in my initial description, ) if I leave the headlight switch off, the alarm and dash lights turn on by themselves. In other words, the headlights are just one of several different things that are going wonky. And the ignition switch seems to be the common factor.

So I am still leaning towards a bad off-position contact. Unless someone feels like talking me out of it

Thanks,
Chris.

 

Disconnect the ignition switch and see if the 'switch-off' behavior continues.

There are too many variables here to pinpoint a definite cause. The fact that the misbehavior involves lights, combined with the model (which has the auto lights-off feature), may mean the problem is in the auto lights-off circuit (Body ECU, courtesy switch, etc.).

The real wild card in all this is the alarm. If your alarm is designed to flash the lights, it could possibly cause such weirdness.

A short in the headlight control stalk (and / or the spiral cable) might also explain it.

There's no way the ignition switch alone could be causing these symptoms, even if it's bad. There are one or more other faults at work here.