Starting two days ago, whenever I lock my doors, the security light goes from flashing to solid, and hours later all of my dash warning lights come on. By morning, it's drained the battery to the point of needing a jump. It does this both when I lock the doors from the inside and outside. There's no problem if I leave the doors unlocked, which is not an acceptable solution. Any ideas where to start looking?

 

sounds to me like the BCM is what's draining your battery.

 

Do they just suddenly go bad? The only thing I did to the car that day was get new tires, which I have a very hard time imagining to be the cause.

If it has gone bad, is it just a software issue, where I can just get it reset?

 

you need a new BCM if it was bad. But it may not be the BCM. The security led is supposed to light up when the door is locked...I'm thinking since you mentioned the battery went dead, maybe the battery is what's bad? Battery or alternator?

Is this with your stock setup, or do you have an aftermarket alram / remote start / something like that?

 

Battery was brand new in December, and this was the very first time it's gone dead. My understanding was that the alarm is only supposed to arm when you lock from outside the vehicle, either with the key or the remote, and that the light is supposed to start flashing after ~30 seconds. Everything is stock.

 

Update: it now happens whether or not I lock the doors.

 

you've got some sort of draw going on here...the part about the dash warning lights coming on all by themselves is weird.

have you tried cleaning your grounds, in the engine bay? you've got some sort of electronic gremlin here somewhere

 

When I bought it, I cleaned the grounds and also added some additional ones. My key-off draw, then, was 60 mA through the windows and BCM. Haven't re-measured yet.

I just now remembered that the day before this started, I unplugged my power antenna.

 

Having unplugged the antenna of course shouldn't create any problems. I assume you plugged it back in, so unplug it and leave it off and see if it makes any difference.

Disconnect the battery for a half hour to reset the various modules in the car like the BCM, the ECU and everything else.

I've read of several cases where the Bose radio will somehow fail and draw power when it is off, so another thing to try is unplug the radio.

 

check your master window switch, unplug it and see if it changes anything.

 

I intentionally set off the alarm and then deactivated it. I let it sit from noon to midnight today, as long or longer than its usual overnight. Problem is gone. The difference between today and before is that the other nights it got down to low 30's, and today was much warmer. However, it's gotten colder than that before this problem surfaced. Is there a possibility of a temperature-driven short in, for example, the ignition switch?

 

Problem returned yesterday after being parked for three hours. I have replaced the ignition relay, in hopes of not having to replace my ignition switch.

 

Dash lights don't come on with relay disconnected, so that's eliminated.

Lights also don't come on when ignition switch is disconnected. However, if I disconnect the switch WHILE the lights are on, they remain on. Suggestions?

 

Popping the hood makes the lights go out. The hood switch is taped shut, so there must be a short somewhere in the engine compartment. Measured battery load to be 55 mA.

 

Try removing the security fuse and see if the problem continues. The factory alarm is only good for keyless entry. If that doesn't work check the headlight switch itself, then the bcm.