sub cutting out.

[matt77303]

So my mk3.5 had the ford factory sub woofer installed, which a was worse than useless. So I've moved over my sub install from my old cae. Fitted, all wired in and I've tapped into the Ford subwoofer loom to get signals.

All works perfect for about a week, then it's like the head unit stops outputting the sub output. The amp is still powered and the amp lights are on as normal. I'm 99.9% certain it's not loose wiring. As when it goes off wiggling all connections doesn't result in it coming back on.

Only way to get it to come back on is stop the car, get out. Lock it. And then start it again. And it can stop mid journey.

Any ideas anyone?

Matt

[mjt]

How does the impedance of your old sub compare with the factory-fitted one? It sounds to me as if the amp maybe has overload protection which is tripping.

[matt77303]

Cheers.

I'll dig out the old sub and have a look.

Matt

[Karl Thomas]

Hi .

I know this is an old thread but did you get to find the reason why the sub  cuts out  as i am having exactly the same problem with my 15 plate ST with the 10 x Sony system . I have a Audison Prima 10' active sub and have even had a LC2I controller fitted and it still does it . All brand new fitted by a reputable audio installation company and they dont know either . This is driving me insane.  Doesnt anyone have any idea ?.  Its not the wiring or the Audison unit as they changed it to another one and it still does it . When it cuts out the only way you can get it working again is lock the car , wait a couple of mins , unlock it , turn stereo back on and then it works fine again until it does it again . Unit is not over heating , its not the wiring . Anyone , please ?

[alexp999]

It’s a software issue. If you are picking up the sub signal you can’t fix it.

Its probably better to switch to your own HU, or maybe have it connect to the door speaker signals so it’s not relying on the buggy sub signal from the factory unit. 

[Karl Thomas]

7 minutes ago, alexp999 said:

It’s a software issue. If you are picking up the sub signal you can’t fix it.

Its probably better to switch to your own HU, or maybe have it connect to the door speaker signals so it’s not relying on the buggy sub signal from the factory unit. 

Hi mate .

I am not taking the signal from the sub, i tried that . I have also tried taking it from the rear Speakers , that didnt work either . Now i am taking it from the front , still keeps cutting out . Im really begining to dislike this car . Any other ideas ? 

Cheers 

[Karl Thomas]

Just now, Karl Thomas said:

Hi mate .

I am not taking the signal from the sub, i tried that . I have also tried taking it from the rear speakers , that didnt work either . Now i am taking it from the front , still keeps cutting out . Im really begining to dislike this car . Any other ideas ? 

Cheers 

Also , you cannot connect an aftermarket headunit and get all you car controls to work on it , ive already enquired into that .

[alexp999]

It must be the bass frequencies cutting out in software completely if it affects all Speakers then.

There is no way to fix it while relying on the factory head unit that I'm aware of.

Is there anything in Sync 2 you actually need for the car?

[alexp999]

Just one thought, but I don't know if the "non Sony" standard fit HU (ACM) is any better. If it's not driving the Speakers but just providing a signal, it wouldn't matter that it's a lower spec.

[Karl Thomas]

On 4/6/2023 at 9:05 AM, alexp999 said:

It must be the bass frequencies cutting out in software completely if it affects all speakers then.

There is no way to fix it while relying on the factory head unit that I'm aware of.

Is there anything in Sync 2 you actually need for the car?

The rest of the Speakers in the car work flawlessly as does the factory sub under the boot carpet on this 10 x so called speaker system . I even changed the Sync 2 to a Sync 3 still the same . Ive really had enough of this car . I cant believe there are only 3 people that have an aftermarket sub and amp and no one has a clue how to fix this issue .

[alexp999]

It’s the audio control module that’s the problem rather than the sync APIM. 
 

You’ve said that the rest of the Speakers work, but they must be losing bass frequencies when the issue happens or tapping in to the front and rear Speakers would be reliable for the new sub. 

[Karl Thomas]

I have tried taking the signal from the cars oem sub wires , then rear speakerwires and even the front speaker wires , makes no difference what you tap into , it makes 0 difference . Have to lock car   leave a few mins , unlock then works fine again . Volume doesnt need to be bigh for it to cut out either , still cuts out at low volume . Such a crap systen in these cars . My mates have the MK2 STs , no issues with their cars .

 

[alexp999]

Which means it’s a software issue and the bass frequencies are cutting out from the audio signal rather than a particular speaker channel. 
 

I’ve only heard of it happening on the Sony system. Might be worth considering a “downgrade” to the standard non Sony head unit and have your own amp to drive the Speakers  

[Karl Thomas]

Well guys, i have found the problem . You wont believe this ... since my last post the weather has picked up quite a lot . My sub/amp has been working flawlessly but only when the air con is switched on to the cold setting , but the Audison active sub is not getting hot at all . I changed the audio control module for a new one . Sub/amp still only cuts out when you turn the air con off so made no difference . So something is getting hot which is why its shutting down , nothing to do with firmware or signal cutting out .

[alexp999]

I don’t think temperature is the issue. It does this all times of year afaik. Unless you’ve noticed a massive increase in frequency with the hot weather lately?
 

The reason I say it’s the firmware/software on the ACM is because the fault before that used to cause static intermittently. An ACM firmware update fixed that but then introduced the cutting out issue instead. 
 

But it’s interesting that the AC might affect it. I wonder if it’s tripping over something on the canbus being communicated by the AC controls.