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This is an old problem. The car horn alarm goes off sporadically. I can't pull the fuse or I'll have no horn. I don't want to diagnose it at the dealer because it is 10 years old.
Is it possible to cut a wire that leads to the horn without disabling the horn? If so, can someone share a wiring diagram?
Thanks!
 

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6Crew has the full workshop manual hosted: MAZDA 6 FULL WORKSHOP MANUAL!!!!!!!!!!!!

But I definitely don't advise just cutting cables without trying to find the source of the problem.

- Aftermarket alarm/stereo installed?
- Battery Cables nice and tight and clean?
- All your grounds are secured properly?
- No frayed wires anywhere?

^^ All things that could cause a random electrical issue.
 

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I've read from a few sources that the micro-switches in the door locks corrode and break contact, making the car think a door has been opened. Stick a WD-40 straw in there and douse the latch. Open and close the door 20 or so times to get the liquid into the latch and help clean the corrosion out of it.
 

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To help others avoid this same tale of woe and the possible expense involved rather than a simple can of WD40...

We got a used 2009 Mazda6 recently, which we knew had the random alarm issue along with a broken fob, plus it smelled damp inside....

We took it in and was then at the dealer for over two weeks trying to fix it:

They found and fixed a water leak that was going down into the ECM- they replaced it, but alarm was still going off.

They replaced and reprogrammed a new fob- alarm went off when they brought it up to the front area for my wife to pick it up.

They had already checked the battery of course, which was just two months old and it tested stronger than specifications. (After all this when back home, I measured it myself and it’s a strong one at about 12.4 volts when car is off.) Dealer had recommended changing it anyway at $160, but being quite a bit poorer already that’s when we fetched it and went to AZ where it was bought and it checked out fine on their tester. So we took it back to dealer and said no thank you on a new battery.

Next they tracked through the stored codes after the ECM was replaced, and it was showing a back door sensor tripping- so they replaced that but.... alarm went off again within a few hours of bringing it back home. Grrrr!

Meanwhile, I’m out $1,300 and it’s still got a gremlin running loose in its dang electrical system!!

.... read here about the WD40 trick, so I got out the can and heavily sprayed all door, hood and trunk latches, then opened and closed them a dozen times and voila... no alarm issues for a week now!!

I wish I’d seen the trick for trying WD40 about three or four weeks ago!!!!!
 

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I tried WD-40 on all my latches but am still getting frequent alarms. Coworkers will come tell me my car is going off all the time. A few weeks ago I had to work an early morning shift and noticed that the rear dome light was coming on when I took turns or drove on rough road. I turned on the front dome light (on when doors open) and noticed that it happens a lot more often than I previously thought. Today I reached over and pushed the passenger door and the light came on for a few seconds.
The other issue I've had is that though the battery charges, if I don't drive the car every day, the battery will run down enough that I have to jump the car. I've been using a battery tender every weekend to combat this.
I previously thought the battery issue and alarm were unrelated but have realized that the door switch is triggering so often that along with having the car honk for 30 seconds every time it happens, it is also waking up the BCM and slowly killing the battery.
This weekend, I plan to remove the front passenger door latch and clean any corrosion from the switch contacts. I'll try to get photos of the process.

~Mike
 
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