Alarm going off with new aftermarket head unit 2012 CX-9 Bose Amplified

Hi All,

Hoping for some help on a frustrating issue. I've installed an aftermarket head unit in my 2012 Bose Amplified CX-9, using AERPRO harnesses, including wiring up the amp trigger wire from the unit to the harness. When I turn the ignition key to ACC, the system works perfectly. I get sound, radio, android auto etc, all great. However, when I turn the ignition key to ON or START to actually start the car, there is a blaring alarm sound that starts, goes off every couple of seconds, and never stops. I've tried with a different brand of head unit, same thing. I've checked with AERPRO who have confirmed everything is wired up correctly, and they have never heard of this issue. Clearly there are plenty of people who have installed their units in the Bose Amplified CX-9 fine, so I don't know.

This has been discussed years ago on a couple of forums;



With the only fix being suggested that you turn the ignition key to ON/START first, before ACC. That doesn't work for me.

Where could the issue be coming from? Is there a fix? What even is the purpose of that alarm? If there isn't a fix, would simply replacing the amp with an aftermarket amp work? Is amp replacement a DIY job for a fairly enthusiastic novice?

Thanks in advance!
 
Recently had an aftermarket amp and sub replaced in my CX five with the factory Bose. It’s quite possible that whoever wired it up, did not wire the remote cable correctly, which is wire experiencing battery drain. This can cause all kinds of electrical issues as Mazda are known for having problems with batteries that are beginning to fail.
 
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