Intermittent partial audio dropout on 2014 Cooper S

[parkerm49]

Looking for some advice before I hand my 2014 Mini Cooper S (F56) over to a Mini dealer and start haemorrhaging money on diagnostics…

Car is a 2014 Cooper S with ~80k miles and the Harman Kardon audio system.

I’m getting intermittent dropout of the driver’s door midrange speaker and A-pillar tweeter when driving over bumps. The behaviour is very repeatable:

• Audio works perfectly for several minutes
• Hit a bump → driver’s door midrange + tweeter cut out completely
• Hit another bump later → they suddenly come back to life

The problem became much worse over the last couple of very hot days when the car had been parked in the sun and the cabin got extremely hot.

However, I’ve just tried it again early this morning with the car completely cool, and there’s no improvement — the driver’s door midrange and tweeter are still dead.

Before the dropouts started, I’d occasionally get a loud thump/crackle from those speakers over bumps, but the audio itself generally kept working.

A few other symptoms that may or may not be related:

• I can get thumping/crackling from those speakers even with the audio system switched off when driving over bumps
• The midrange speaker sometimes emits a low buzzing noise even with the ignition off
• Occasionally I can hear a faint “digital traffic”/data-noise type sound with the ignition on

One thing that makes me suspect this may not just be a simple broken wire or bad connector is that, even when the speakers are “not working”, I can still sometimes hear faint buzzing/noise from the midrange speaker.

If the speaker connection was going fully open-circuit, I’d have expected complete silence rather than low-level noise, buzzing, or occasional faint “digital traffic” sounds.

That makes me wonder whether the amp channel is unstable/oscillating, there’s a grounding issue, or there’s some sort of partial/intermittent connection rather than a total break.

I believe the driver’s door midrange and tweeter are both driven from the same HK amp output channel, which also seems relevant given they fail together.

Things I’ve already tried:

• Opened the driver’s door and moved/jiggled the rubber wiring loom gaiter between the door and body
• Checked and jiggled the accessible connections to the Harman Kardon amp in the boot (through the rear light access panel)

Neither test provokes the fault or brings the audio back, which surprised me because I initially assumed broken wiring in the door loom.

Are the Harman Kardon amps in Minis known for developing failing/intermittent channels as they age, particularly with heat involved? Or are wiring/connector faults still the more likely culprit?

Has anyone with a Mini — or any other car with a separate amp setup — had similar symptoms?

I drive in Gloucestershire, so there’s certainly no shortage of potholes available to provoke the issue, which is making this particularly irritating to diagnose…

I’m trying to work out whether this sounds more like:

• broken/fractured door loom wiring
• a failing HK amp
• bad connector/contact issue somewhere
• moisture/heat-related issue
• speaker crossover fault
• something else entirely

Any experiences or suggestions appreciated, especially if there are known weak points on F56 Minis.

Cheers,

Mike

[Collectingbrass]

That sounds like a connection issue more than anything else, especially with that many miles. I'd go through the system from head unit to speaker and check all the connections first - copious amounts of eyes on the actual wire to pin connection and contact cleaner when resetting - except on any fibre connections. Rather than a main dealer I would find an audio installer specialist and get them to check it if you need that level of technical input, or have a dig through here: https://www.pelicanparts.com/techarticles/MINI/MIN...

[parkerm49]

Thanks, I'll have a dig through the pelicanparts site. Any recommendations for audio specialists in the Bristol / South West area?