High pitched noise after opening drivers door (no lights on)

[jamsandwiched]

Hey folks,

I've managed to kill my 2017 transit custom starter battery a couple of times now, I think by opening and closing the drivers door - every time I open the drivers door there is a soft, but audible, high pitched noise coming from the engine bay. Any ideas as to what it can be?

I spent the day cleaning my van after being away in it for a week, all rear doors were open for the day so I don't think it was the welcome home lights going on and off all day. All my interior lights have been disconnected so it's definitely not those. I purposely tried to not open the drivers door much but I had to a few times, each time triggering this noise from the engine bay, it persists for a couple of minutes when the lights are off and the van is locked.

I didn't think much of it until today when I went to start the van again and it was totally dead - it's now being charged via a smart charger. It's the second time it's happened now in a very similar situation after working on the van for the day.

Edit: To add, when we're away in the van, once we're parked up for the night, we try our very best not to use the drivers door due to this noise fearing that's what's causing the battery to die. We've opened the side doors/back doors plenty but they don't trigger the noise, and they've never killed the battery when we've been camping etc. It only happens when the drivers door has been opened and closed multiple times.

Any help would be hugely appreciated as it's very frustrating!

Cheers,

Jam

[coonak]

I've get that same noise on mine, its been there since new, no problems with the battery though which is almost three years old.

[Eveshamhardcore]

Mine has always done that.

No problem but I have killed the battery once without explaination (locked on drive) and twice when camping (in and out of the front & back)

[jamsandwiched]

Cheers for the responses folks! I've been camping a lot of the last year but i've never had it die on me regardless of how many times i've been in and out of the back/side doors/passenger. It's only ever happened at home when it's been on the drive and the drivers door has opened numerous times throughout the day. One thing I do want to check is when the dash panel/instrument/radio turns on too, whether it's just when you unlock it or whether opening the drivers door triggers that too.

Even understanding what that noise is would go a long way to figure out if it is what I suspect it is that's killing my battery.

Ideally I need to get my solar panel to charge the starter battery once the leisure battery is topped up.

[Altransit]

Ideally I need to get my solar panel to charge the starter battery once the leisure battery is topped up.

None of the above should affect the starter battery, as it's used only for starting. If the starter battery is randomly going flat, there may be a leak through the alternator diodes that's draining it, or indeed a duff battery

[Woodywoodýwood]

It might be your egr valve. Mine does it and finishes with what sounds like it opening and closing (squeeky metallic sound)