Yes, the alarms have there own power source so disconnecting the battery is a no go. The alarm modules themselves have gone bad and need to be replaced. Not to expensive.

 

Just had a similar situation this morning. The battery is near dead as the key fobs will not unlock the car. However, when I manually open the door, I notice the little stubby lock button doesn't quite make it all the up and out of its hiding position. Normally when I unlock with the fob it the stubby shoots up all of the way.

Well I believe this is what is causing the alarm to shriek as soon as I open the door. The car will not turn over, and the alarm will continue to shriek until I close the driver door. Then the exterior lights flash for a minute or so.

I am noticing some crustations on the battery terminals. Plan on trickle charging the battery this weekend.

 

Has anyone with these intermittent alarm issues seen resolution after installing a new battery? All the threads on this issue don't include resolution posts by the OP after the problem, hope that is a good sign.

I hear of stories of taking the car to the dealer and such, but I may not have that luxury as its in a high level parking structure. I was going to pick up a new battery from the dealer and install where the car sits.

I heard the alarm sounds even when the battery is disconnected, so I hope I don't need earplugs while installing the new battery.

Anyone have experience with this? The car is not sounding the alarm intermittently, only when I try to manually unlock and open a door. I did leave the hood unlatched when I locked the car two nights prior, but even after closing it the key fobs still don't work to unlock and disarm the alarm.

Frustrating...

 

As I've stated above, the alarm modules themselves have gone bad and need to be replaced. I myself went the whole nine yards with dealers replacing this and that with no luck. Had to actually talk to a mercedes dealer to figure out the problem. Ear plugs, pulling the battery, waking up in the middle of the night with the alarm randomly going off... I understand your pain.

Alarm Modules...

Replace them.

 

Thanks for the response, I'll keep the alarm modules in mind if the battery doesn't fix the problem. I'll be sure to post results to aid in future searches.

 

I replaced the battery with a new one from Chrysler (Interstate battery).

Replaced fuses and hit unlock, the alarm is disabled. I jump in and turn the key a notch, everything lights up. However, when I attempt to start I hear click, click, click.

When I attempted to start the car with the previous battery and the alarm sounding, I could get the engine to turn for a sec then nothing.

Now, lights, but no action!

Any thoughts?

 

Did they charge the battery for you? if not, try charging the battery.

 

Went and picked up the battery at the dealer. It appears fully charged as it was "born" on July 2010 and everything lights up with no issues.

 

Sorry for the many reposts guys but I didn't find resolution to the issue I'm experiencing so I wanted to document for future searches.

No erratic alarm issues others are reporting...
Left hood open while I locked the car with the fob...
Couple days later come out to find key fob not able to open car (presumably battery dying), manually open door, set off alarm, tried to start car with alarm on, car will turn over for a sec and quit, open hood and disconnect #9 fuse...
Disconnect old battery and Replace with new one...
Replace #9 fuse, alarm sounds until I use key fob to unlock car/disable alarm system...
Attempt to start car, only get click, click, click...
Pulled out RCM and resoldered contact points (they looked fine regardless)...
Checked all fuses...
Car still will not turn, just click, click, click...
All dash lights come on (including CEL), headlights shine bright, new battery is good...

Next I'm going to pull codes once the Launch Creader IV comes (4-14 days).

 

UPDATE

One little thing I overlooked. Perhaps as part of the immobilising feature, all the doors (left, right, hood, trunk) must be closed when attempting to restart after disconnecting the negative battery terminal as part of a reset. I was leaving my hood open.

I closed everything and the car fired right up! Thank goodness it wasn't a bad starter, etc.

Perhaps this might help others in the future with similar symptoms.

 

My car alarm has been going off randomly for THREE weeks now. I wouldn't mind if it was a simple honk, but it sounds like a siren. Trying to stop it was impossible. In pressing the panic button did no good and after the alarm finally went off my car would make chirping noises... It would only go off in the afternoon or at night waking me up! I took my car into a car alarm/tinting shop and they told me they could not simply remove my alarm because it is factory built.. I have now had my car in another shop for a week and they thought it was the door sensor, but it was not. The alarm still went off! Now they think its the car alarm module.. Am waiting to find out if this is the answer! Hopefully. I just want my crossfire back!!!!

 

Hi Jacqee,

My alarm problem resolved after installing a new battery. The factory issued white battery was six years old and seems to have been responsible. Though the alarm on my car hasn't sounded even once for over half a year, I admit to a little paranoia that it'll happen again somewhere public. I still carry needle nose pliers around in case I have to pull the fuse for the alarm to shut it up. I would have a look at your battery first and temporarily pull the alarm fuse so your neighbors don't start to despise you. In my 2004 Crossfire, it was fuse #9, but check your manual or fuse map before you start pulling.

Ragnarok

 

I think its fuse 11 you can pull to kill the alarm (just check the fuse box as I cant quite remember), you cant lock your doors but it will at least stop the noise. In my car the problem was that the factory sirens had gone bad, so replace them (not a hard job, right up near the wind shield wipers under the plastic )

That SHOULD solve your problem. Hope that helps

 

i found howto solve the problem when i googling. check here

 

I have EXACTLY the same problem, did replacing thr battery in the key FOB work for you, or did you have to do something different?

 

Yes, replacing the battery in the key fob worked for me. It's been years since I did that and it still hasn't happened since. Definitely a good place to start!

 

I had the same prob. changed the car batterie and all ok for over a year now

 

I had this problem with a MX5 in the past...its a nightmare! Hope it never happens again.

So for the X-fire...simplified steps are?

Check/replace Fob battery > Check/replace car battery > Check/Replace Alarm module


and if you take fuse 9 out, for the alarm...can u still drive? Im assuming you won't be able to start it?

 

So for the X-fire...simplified steps are?

Check/replace Fob battery > Check/replace car battery > Check/Replace Alarm module


and if you take fuse 9 out, for the alarm...can u still drive? Im assuming you won't be able to start it?

[/quote]

Sounds like the right sequence to me. I replaced the car battery last year and had just changed the fob batteries a month ago because they were getting weak.
A couple weeks ago the alarm was going off randomly. I just quit locking the doors and had no problems with the alarm for 10 days. I also tried taking out fuse #9 but the lights all flashed which I figured would kill the car battery. So you may have a choice I guess -either disconnect the battery or don't lock the doors.
I bought the alarm siren from Mercedes MB part #A 171 820 25 26 - $148.60 Canadian. Chrysler quoted 282.00 Canadian for #5124443AB (5124443AA was much cheaper but no longer available)
You need to remove the wiper arms and take the cowl piece off to get to the bracket. It has a 13mm nut that comes off from the engine side -the other nut is part of the bracket. You need a T30 security torx (has a hole in the centre)to get the siren off the bracket. The new siren has a male threaded shaft instead of a female thread so you will need a new nut to mount it. I finally found one on an old bicycle seat bracket - worked just fine! Made sure I cleaned all the cowl drain holes before I put it all back together. So now it looks like I have solved the random alarm problem and have the quiet beep when locking or unlocking which is a bonus. Probably only took me 20 minutes including finding the nut.
Needed: puller for the wiper arms, T25 torx for the cowl screws (7) T30 security torx bit and a 13mm socket and a metric threaded nut (same size as the windshield wiper nut).

Hope this helps, Ron

 

Sounds like the right sequence to me. I replaced the car battery last year and had just changed the fob batteries a month ago because they were getting weak.
A couple weeks ago the alarm was going off randomly. I just quit locking the doors and had no problems with the alarm for 10 days. I also tried taking out fuse #9 but the lights all flashed which I figured would kill the car battery. So you may have a choice I guess -either disconnect the battery or don't lock the doors.
I bought the alarm siren from Mercedes MB part #A 171 820 25 26 - $148.60 Canadian. Chrysler quoted 282.00 Canadian for #5124443AB (5124443AA was much cheaper but no longer available)
You need to remove the wiper arms and take the cowl piece off to get to the bracket. It has a 13mm nut that comes off from the engine side -the other nut is part of the bracket. You need a T30 security torx (has a hole in the centre)to get the siren off the bracket. The new siren has a male threaded shaft instead of a female thread so you will need a new nut to mount it. I finally found one on an old bicycle seat bracket - worked just fine! Made sure I cleaned all the cowl drain holes before I put it all back together. So now it looks like I have solved the random alarm problem and have the quiet beep when locking or unlocking which is a bonus. Probably only took me 20 minutes including finding the nut.
Needed: puller for the wiper arms, T25 torx for the cowl screws (7) T30 security torx bit and a 13mm socket and a metric threaded nut (same size as the windshield wiper nut).

Hope this helps, Ron[/quote]


You also have to watch out for the couple of things attached to the bottom of the cowling. I cannot quite remember what they were but a wiring harness and maybe wiper fluid hoses were clipped /attached to the underside of that cowl. I also can't remember if I disconnected the neg batt cable or not. Someone posted before that if you don't the alarm module will go crazy when you pull the plug off of it. Realigning the wires.hoses was a little of a balancing act but yes when you replace that module with the new one, you'll like the soft beeps confirming lock/unlock.