93 Aero with resident woodpecker

[dadofbud]

Yes strange title, but I'm hoping it's grabbed your attention as I need some help please.

We have a 2004 93 Aero, much liked if a little thirsty.

Anyway 9 times out of ten when the car is unlocked there's a sound similar to a wood pecker which can be heard by others walking by in car parks. (it's that loud)

This is almost a "plastic type" knocking sound as appossed to metallic sound.

It's coming from the dash near side and it's driving everyone nuts.

So far I've checked the door solenoid locks in an attempt to exclude things it can't be.

Any suggestion other than ear plugs would be most welcome

Thanks

Bob