Alarm acting strangely, found the reason

[jembo]

Well, the factory alarm on my LS sometimes likes to act as if someone is trying to break into the car when I press the unlock button on my keypad. This will happen once every 10 or so times that I go to unlock the car, and I figured out what's causing the alarm to trip.

When you press the unlock button once on the keypad, only the driver's door is supposed to unlock. Well, sometimes all four doors unlock instead, and that's what causes the alarm to sound. And yes, I am sure that I am pressing the button only once.

Has anyone heard of it doing this before? Any guesses as to why it may be happening?

 

[joegr]

I don't know about the year of yours, but on both of mine (04 & 06) it is an option on the setup menu. You can set them to work as you describe (unlock driver's door on one press, and unlock passenger's doors on second press), or you can set it to unlock all doors on the first press. This is how mine are set, and I think that was the default.
Maybe if you set yours to all unlock, then the alarm problem would go away?

On a side note, I've had false alarms on both cars maybe once or twice. The very few times it has happened, it was when opening the trunk with the remote.

 

[97stscaddy]

Mine has gone off if I close the trunk when the rest of the car is locked.

So normally when you press unlock on the remote only your drivers door unlocks. But only once in a while it will unlock all of the doors instead?

 

[jembo]

I don't know about the year of yours, but on both of mine (04 & 06) it is an option on the setup menu. You can set them to work as you describe (unlock driver's door on one press, and unlock passenger's doors on second press), or you can set it to unlock all doors on the first press. This is how mine are set, and I think that was the default.
Maybe if you set yours to all unlock, then the alarm problem would go away?
.

I have an '01, and it does not look like that is an option.

So normally when you press unlock on the remote only your drivers door unlocks. But only once in a while it will unlock all of the doors instead?

Yes, that is the problem.

 

[milehighmikey]

Sounds like a double-send of the signal from the key fob, as in having dirty or corroded contact membrane inside. A cleaning with technical grade isopropyl alcohol or contact cleaner may clear it. Mine does doubles on the lock function on occasion, as evidenced by the beep which only happens with two remote lock presses within 5 seconds.

The trunk will sound the alarm if you only press the trunk open button on the fob without unlocking the car first, at least on my 2000. It goes off after around 20 seconds of opening it with no prior door unlock.

 

[97stscaddy]

Double send? Might explain why mine beeps the horn sometimes when I've only pressed the lock button once. What do I look for in the remote that would cause this? Ive pulled it apart and it seems to be squeaky clean...?

Which brings up another question... There are 5 contacts inside the remote, yet there are only 4 buttons on the outside... :shifty: What's the fifth contact for?

Mine always went off when I closed the trunk. But maybe I only had it open for 20 seconds? I dunno. I kinda figured it was because the car was locked so I started unlocking it before I open the trunk, hasn't happened since.