Electrical gremlin...

[Will]

I hate electrical problems, but I've got one that I hope someone has experience with and can help.

TL;DR: could it be the Final Stage Resistor? I'd hate to replace it since it sucks to access.

Car: 2003.5 e46 m3.

Additional equipment:
- BlueBus. I've had this since the first batch, and run the latest firmware. I've never had that IHKA problem even with old firmware.
- Autodimming rearview mirror with compass and homelink, I believe from a e90. This was relatively new, but no problems with it after installation. Had for a few weeks without problems.

In sequential order:

- Noticed that the IHKA / climate control panel was stuck on high fan. None of the buttons work. Cannot change temp, vent settings, a/c on/off, etc.
- Shut off car, restart the car and problem persists.
- Disconnect battery, reconnect, and all's well. The climate control panel works normally, again. All's well.

... a few days later:
- Get door chime when door is open, as if key is left in the ignition (but key is not in the ignition). This is strange.
- Then, notice the keyless entry doesn't work. Don't have time to mess with it, so park it for now and lock using key.

- Then, a few days later I go and drive it:
- Notice the door chime key-in-ignition thing still, but key is not in ignition.
- Keyless entry works again, to unlock and lock .... but the siren is set off within 30 sec of locking / arming.
- Try arming the alarm and disabling motion sensor (read online a second press of lock button on key does this. Urban legend? who knows). No change. Siren still goes off. Door chime still there.
- Unplug the rearview mirror. No change. Both the door chime and the siren still goes off. Plug in the rearview mirror again.
- I unplug the hood switch and try keyless lock / arm... no change. Siren still goes off within 30 seconds of locking / arming.
- Remove one of the two Anti-theft system fuses. Siren doesn't go off.

So, now:
- I still have the door chime thing,
- No alarm siren because one of the two fuses is unplugged.
- keyless entry works intermittently, but works the last 5 times I've tried.
- battery voltage: 12.53.

Final Stage Resistor?

[johnrando]

FSR is infamous for a parasitic battery drain.

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[Will]

I think I'll bite the bullet and just try the FSR.

[sillieidiot]

Hmm, it kind of sounds like gm5 going bad to me. Since it's affecting alarm and keyless entry. Usually FSR going bad just kills the battery.

[Will]

Hmm, it kind of sounds like gm5 going bad to me. Since it's affecting alarm and keyless entry. Usually FSR going bad just kills the battery.

GM5! yes, I totally forgot about this module. I wasn't sure it was the FSR because it involved the alarm, and keyless entry. All the FSR failures are inability to adjust fan speed and dead battery. I'll look into this GM5 thing.

Has anyone tried this guy, apparently in Torrance area of LA: https://www.bmwgm5.com/default.htm

[sillieidiot]

GM5! yes, I totally forgot about this module. I wasn't sure it was the FSR because it involved the alarm, and keyless entry. All the FSR failures are inability to adjust fan speed and dead battery. I'll look into this GM5 thing.

Has anyone tried this guy, apparently in Torrance area of LA: https://www.bmwgm5.com/default.htm

Yeah, he's well known on e46fanatics for fixing these. Should be your go to.

[johnrando]

Hmm, it kind of sounds like gm5 going bad to me. Since it's affecting alarm and keyless entry. Usually FSR going bad just kills the battery.Good call!

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[Will]

Just an update:

- I still have the door chime thing, [resolved]
- keyless entry works intermittently, but works the last 5 times I've tried [resolved]

But here's what's weird, I didn't do anything.

Now:
The alarm will sound within 10 seconds of using remote to lock. I unplugged hood switch, still goes off. I changed hood switch, still goes off. So now i lock the car with the key to prevent the siren from going off. I'll mess with it later.

This car has ghosts.

[sillieidiot]

hood switch might not be making contact with the hood to press it all the way down? What happens when you lock the car while holding down the hood switch?

[Will]

hood switch might not be making contact with the hood to press it all the way down? What happens when you lock the car while holding down the hood switch?

No change. The siren still goes off after about ~5 seconds.

I've tried disconnecting the switch. No change, still goes off after ~5 seconds.

I've set the alarm and held down the hood switch with my finger, then released the switch (simulating opening of the hood), and alarms goes off as it should.

Another thing I've noticed is that the beep to signal locking and unlocking is very faint. The siren is normal volume.

... ghosts.

[sillieidiot]

maybe it's one of the other sensors, like the tilt or interior sensor going bad?

[t.er]

Another thing that could affect the alarm are the windows. I've noticed with mine that if I open the door, disconnect the battery, and close it, the window goes lower and lower as it thinks it needs to clear the seal even if it's already cleared. Far fetched but maybe try opening and closing your windows and sunroof?

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[Will]

Small update:

I contacted that GM5 guy with the symptoms and he replied that it's not the GM5 module.
I changed the tilt sensor in the trunk with another one I had, no change. Siren still goes off after 5 seconds of locking the car with the key.
I unplugged the interior sensor and the siren doesn't goes off anymore. Behavior seems to be as it should, albeit without the interior sensor.

Seems like a new interior sensor might be needed.

Thanks to everyone for the ideas, I'll report back after I have some time to mess with it again.

[sillieidiot]

Hopefully that's it. You could borrow my interior sensor to test, if you want, before you buy another one. It's not like my car moves lol