Banging Noise Coming Through Speakers When Radio/CD Turned Off

[BorisBolero]

My 2008 Swift Bolero has intermittent loud banging noises coming through the speakers even when the radio is turned off. I first noticed this a few years ago when I connected up a new leisure battery. It lasted for an hour or so then did not recur.
This has started to happen again whether the control panel over the door is on or off. It doesn't happen (yet, anyway) when on electric hook-up and the leisure battery is charging, and happens more often while off charge and the leisure battery voltage drops below 12.3 volts. Can't see how the leisure battery in any way relates to the cab radio, but it seems to be! The noise is really loud and sounds like someone hammering on the outside of the van. It lasts for a minute or two then stops, then randomly starts again. Has anybody got any bright ideas please as the only way we can use the van at the moment is with electric hook-up.

 

[Wabs]

Sounds like a short to me , have you checked the fuses?

 

[Wabs]

If your battery drops to below 12.4, it’s normally buggered,,maybe test the battery

 

[BorisBolero]

I'm no electrical genius but have removed the fuses that the handbook says are for the sound system (in the hope of shutting it up) and the radio still works - so not got very far

 

[Wabs]

Do you have a multi meter?

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[BorisBolero]

The hab battery was a new one just before we set off a few weeks ago and was fine for 2 weeks before the problems started again when we spent a couple of nights off-grid

 

[BorisBolero]

Don't have a multi-meter with me but going home tomorrow. The display panel has always been fairly accurate for voltage though.

 

[Wabs]

That’s a weird one, there are peeps far more savvy than me here, I’m sure someone will give better advice

 

[Swifter]

Does this happen in multiple locations or just when parked up at home ?

 

[BorisBolero]

Thanks for your thoughts anyway

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[BorisBolero]

It has happened at several locations, all off charge

 

[drpeej]

I had this problem in a Skoda Octavia some years ago. I used to get alarmingly loud crackles and bangs even when the radio was switched off.

The problem was caused by water that had entered the driver door innards and caused the wiring loom connector to become badly corroded.

Solution was to trade the car in for a new one

 

[Gellyneck]

I'm no electrical genius but have removed the fuses that the handbook says are for the sound system (in the hope of shutting it up) and the radio still works - so not got very far

You're media centre may well have a keyed supply from the vehicle battery (standard factory ISO fit) and a dedicated permanent live supply from the leisure battery (fitted by the convertor - Swift). This enables the media centre to be permanently powered rather than having to have the ignition on permanently and giving the issue of draining the vehicle battery.

We have had a reverse issue on our media centre with the cooling fan running even when switched off when motorhome plugged into ehu and the battery charger being switched on. Solved this by fitting a dedicated "kill switch" on the permanent live from the leisure battery.

Pulling the fuses on the factory ISO wiring loom will not disconnect the power supply from the leisure battery.

Suggest you look to see if you can disconnect, temporarily, the permanent power supply to see if this cures your issue. Down sides are that you won't be able to use the media centre when parked up and you may well have lost the radio pre-tuned settings when it's powered up again. Funnily enough our media centre has a built in DVB-T tv tuner and it doesn't lose the pre-tuned settings for this. Make sure you also have the radio code as you may need this.

 

[BorisBolero]

You're media centre may well have a keyed supply from the vehicle battery (standard factory ISO fit) and a dedicated permanent live supply from the leisure battery (fitted by the convertor - Swift). This enables the media centre to be permanently powered rather than having to have the ignition on permanently and giving the issue of draining the vehicle battery.

We have had a reverse issue on our media centre with the cooling fan running even when switched off when motorhome plugged into ehu and the battery charger being switched on. Solved this by fitting a dedicated "kill switch" on the permanent live from the leisure battery.

Pulling the fuses on the factory ISO wiring loom will not disconnect the power supply from the leisure battery.

Suggest you look to see if you can disconnect, temporarily, the permanent power supply to see if this cures your issue. Down sides are that you won't be able to use the media centre when parked up and you may well have lost the radio pre-tuned settings when it's powered up again. Funnily enough our media centre has a built in DVB-T tv tuner and it doesn't lose the pre-tuned settings for this. Make sure you also have the radio code as you may need this.

Many thanks, I hadn't thought of that, I will have a look for a fuse in the Swift control box and see if I can silence the speakers that way. Would be very happy to be without any sound system, at least temporarily, if we can avoid the heart attacks when the banging starts!

 

[pappajohn]

If your battery drops to below 12.4, it’s normally buggered,,maybe test the battery

12.6v is fully charged and rested
12.4v is around 50% discharged.
12v is considered flat
10v is considered knackered and very unlikely to hold a charge.

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