My '05 Crossfire SRT6 w/ 12K miles is great except when the extremely loud siren goes off. Most of the time when I lock the doors with the FOB, the lights and siren will start flashing and going off about 5 to 15 minutes later. I try stopping them by pressing any of the three buttons on the FOB with no success. After what seems like hours (5 minutesą), it will stop. One time the alarms went off a few minutes after I started driving it. The doors lock when the car is in motion.

The car is still under warranty. The dealer has looked at it twice. No codes. Does not know what to do.

Help.

 

Original battery? If so, change that puppy.

 

Change the main battery, the FOB battery, or the security battery?

 

Main battery.

When the battery gets some age on it, it tends to allow a slight dip in voltage. Mercedes vehicles behave VERY oddly when this occurs...

If the battery is original, it's over five years old. Time for a new one!

 

There was a TSB years ago about the red panic button sticking causing the batteries in the remote to drain...TSB 08-030-04 thats the only thing I can think of....

 

Your engine battery is probably the culprit. I had the same thing happen and that was the cause. It gets worse though - if you leave the vehicle without locking it and battery drops more, the machine locks everything and you can't get in! Key won't work, nothing!

I had that happen and had to have it towed to a Chrysler dealer. They went crazy trying to figure it all out. I put the biggest honking battery in it I could find. Like a previous poster said, there 5 years old now.

 

One other thing to consider is the alarm module in the trunk. If you have an undiscovered leak and water is getting down into the trunkwell it could affect that module as well a host of other things. You may start to have lighting issues and power lock problems. It is a pita to get to as you have to remove the black foam block that is under the trunk mat on the passenger side, and that is preceeded by removing about 4 interior panels.

Better yet, crawl under the car and remove one of the three rubber plugs found at the bottom of each trunkwell. They are round bumps about the size of a dime and covered with undercoating. If water streams out you have found a problem.