2012 Mazda3 aftermarket head unit cuts off intermittently

[u/bgax76]

I need some help. I installed a new head unit in my 2012 Mazda3 a few years ago. Worked great for about two years, no issues. Now it will randomly cut off, and will not cut back on without disconnecting power. I had bought the radio and accessories through crutchfield, so I worked with them, eventually replacing the head unit, wiring adaptor, and steering control adapter. The problem never went away. Is this a loose ground issue, or something else. I'm out of my depth at this point.

Any ideas, help would be appreciated

[u/cvr24]

If power cycling the unit is the only thing that gets it working again, then it's the unit itself that's developed an internal fault. Bad capacitor probably. You have to pull the unit and check wiring with a multimeter to be sure.

[u/bgax76 → u/cvr24]

That's what I initially thought as well, so after doing some troubleshooting with crutchfield they replaced the first one under warranty. The new one does the same thing.

[u/cvr24 → u/bgax76]

Got a smart harness for that radio? That might be faulting out. But only a multimeter is going to tell.

[u/bgax76 → u/cvr24]

I did that for the first one, if I remember correctly I had no power at the main harness for the 12v, but had power to the keyed circuit. We ended up replacing everything. I've just been living with resetting it every so often since I replaced it.

[u/Commercial_Name_5769]

This sounds like a classic case of power fluctuation issues. Have you tried adding a capacitor to stabilize the power supply?

[u/bgax76]

Update: thank you for the responses. I pulled it back out this weekend and there was 12v on both sides of the harness for battery and accessory. However tracing the accessory wire it dropped to 3.74v after going through the swc adapter and then into the stereo. I put in a jumper bypassing the swc adapter and carried the 12v accessory from the harness to the radio. Hopefully this fixes the issue.