Factory alarm going off multiple times a day

Hello all!

I was a long time member over on the MSF forums but have been off there for a very long time, and just found out they are no more. I am the original owner of an '07 MS3 and still loving the car but this issue is driving me nuts. I don't have the time, money or know how to try to track down what is surely a short in the wiring or door sensors or I don't know what else, or to pay the dealership to do so

Typically a day after any rain, my factory alarm will start going off several times a day for several days. This is driving me insane. My only options that I'm aware of are to either leave the doors unlocked (obviously not safe) or to pull the horn fuse (assuming there is a fuse just for the horn...also not really safe but that's what I'm likely going to do next).

Is there any way to disable the alarm so I can at least lock the doors but stop the honking without losing my horn?

 

Not sure about disabling the alarm that being said sounds like a symptom of a dying battery wife's car used to do the exact same thing 3 raining and it'd go off.

Also welcome to mso.

 

Unfortunately not the battery. I replaced the battery late last year when it started getting weaker from the cold. And this has been going on for a couple years though it's gotten a lot more frequent over the last several months.

The car starts quickly without issue and starter cranks very strong, even when it was sub freezing.

 

My ms6 did this as did will Dawson's fron PD tuning. It was our factory BCM ground being corroded. Not sure where it is on thr ms3. But on the ms6 its right in front of the fuse box in thr engine bay. We both cleaned ours up with wire wheel and resecured em and it corrected the issue

 

You can try by removing F57 in the passenger junction box (fusebox) which is labeled alarm, but it may disable other functions, including ignition in your car.

The door latch mechanisms in the door may be shorting due to water ingress. Car is older and if something isnt sealing right, the system may think someone opened the car without the key or fob. I have heard and seen this happen on Mazda 3.

This may be tough to diagnose without the right tools because it could be any door causing this.

I don't know how much access you might have or if you are willing to dig into your doors, but disconnecting a different door latch after every rainy day may help you isolate the problem. If you don't need electronic functions in your door, you can probably just disconnect the door with one connector at the bottom of the Apillar, that way its minimal part removal.

 

Here is the fuse box and the two ground wires I see in front of it. Are these the same you're referring to? They don't look bad to me.

 

I suspect this as well. It doesn't help that this car had minor accidents on both sides so the doors may have been taken apart to fix the damage. I can deal without the locking and windows of one door at a time for troubleshooting. So I have to remove the plastic cover of the A-pillar and there should be a connector there for each door on that side?

 

I have this issue intermittently with my 2010. I previously researched it and was pointed toward the BCM, as @Sho said, which is apparently in the cabin for genpus. So far I haven't tried to fix it bc I noticed that 99% of the time it only does it if I park in a certain section of the lot at work...so I just park elsewhere instead of digging into wiring and shit lol.

 

Haha now that is even more weird. I like the idea of disabling the power to the doors one at a time to track down which door. I'll look at the a pillar cover to see how it comes off and see what is back there.

 

Should be a connector on the rubber grommet. The release levers are on the top and bottom, hard to feel. I could be referring to the rear doors here, so maybe start with the rear doors as they are easier to access. and if possible, start with the doors that experienced the accidents.

 

had this issue with mine. Something was up with the door lock actuator or something. The car would think that the door was opened when the car was locked and then it would sound the alarm. Took it to a dealer and it didnt happen for a while. had to floor it cause some honda loser was riding my ass and it said my passenger door was open after haha.

Ill probably check the BCM when im not lazy as Sho said

 

I had an issue where it wasn't the alarm going off but just that the cabin light would stay on randomly and sometimes the doors wouldn't lock. It got worse and if I hit a big enough bump on the highway the car would flash the interior lights on and off as well as indicate a door open. Thankfully genpu tells you which door is open and after a few months I was able to catch it on the display. Unplugged the latch assembly in the passenger door to confirm and then replaced. It's been fine for two years now. Though I was lazy and didn't disconnect the battery and fried my bcm which is a while other discussion.

The bcm in a pu is above the driver's left knee. Unfortunately you have to take the whole center console and under dash out to get to it. I would bet it's in the same spot in the juan

 

lmao on second thought maybe this can wait

 

It's not bad it took me about 1.5 hours to get to it and about .75 to put it back

 

Would you be able to post a pic or two to give me a better idea? You're saying there are release levers to get the A pillar covers off?

 

I was referring to the harness connector, but I may have been thinking of a different vehicle haha.

I actually think you should attempt to disconnect the connector from inside the car without removing the plastic housing from the metal car frame.

 

I'm thinking this is on the edge of the door? Hahah I really need to go out and look at the car. Been teleworking and not driving much. Worried if I pop that off though, what do I do with it to make sure it doesn't get pinched in the door?

 

I'm 95% sure this is the connector in your diagram (pic attached), but I am not sure how to get it out of the body to expose the clip in the diagram. I'm afraid to rip that cover and risk more water issues. Can anyone give guidance on how to get this out of the body and expose that clip?

 

Hey, busy time in my life, I go missing at times.

That is the connector. I was referring to disconnecting it from inside the car. You need to remove the plastic trims inside to get to it, but some cars are not accessible. I have not removed these on a Mazda 3 in the recent past, so I cant remember the details.

The rubber grommets are usually robust, just don't take anything sharp to them. They are a pain to work on in the tight door jam space though... and once you pull off the grommet, you will likely have to remove the connector to reseat it.

The connectors have plastic tabs that need to be pressed in to release from the door.

Have a look here for a guide.
http://www.mazda3tech.com/front_door_removal_installation-562.html

 

Awesome, this helps quite a bit, thank you!