Help with central locking problem

[velo2453]

Greetings. New Boxster owner here, a 2002 S.

I'm having an odd problem with the central locking system and was looking for some suggestions. The car will occasionally lock using the keyless remotes, and then usually only when the batteries are new. Other times when you push the button it does nothing.

When it DOES lock, when it unlocks either from the remote or using the key in the lock I will sometimes get the double horn fault, while other times it operates normally.

The Durametric shows no fault codes with the window or lock sensors, nor with the alarm control unit, and all window functions seem to be normal (drop with door handle pull, normal operation with switch).

One oddity is that the batteries in the remote only seem to last a week or so. This is sitting on a ring unused, so its not pocket activations burning it down. The problems seem to get more frequent when the batteries are low - not just with the remotes, but also the central locking while using the key.

I'm a little stumped. Next steps were going to be pulling the alarm control unit to see if there's any corrosion (floor is not wet). Anyone else had a similar situation? I know it's pretty common to have locking issues but most of the things I've found have other causes clearly associated.

Thanks!