07 A6 Avant 3.2L Quatro

The doors still lock, the little red light still blinks on the door sil. But there's no longer a "beep" when locking with the remote; and the corner lights don't flash as they did?

Any ideas/suggestions where to start?

Thanks!

 

Pretty disappointing that I got NO responses to any of my three posts asking for help; but that won't keep me from trying again:
I've isolated the problem with the non-beeping locking system to the passenger door. There I found a rubber cap, with a slot and a picture of a lock, on the same door surface with the lock. The slot was intended to let you pry the rubber cap out of the door. And under the cap is a cream colored plastic "cam?" with it's own similar slot, to make it possible to turn with the key.

So, I've experimented with this little cam: If I place my key into the slot and turn the cam 180 degrees clockwise, and lock the car; voila...the beep is back. But when I unlock and relock the Avant without turning the little cream colored cam, then nothing, no beep, and it may be the passenger door isn't really locked. (Still trying to figure this out...)

I've been through the 07 Avant's Operators Manual twice, from cover to cover, and I can find NO, NONE, NOT ONE reference to these little rubber caps or the cams under them. (They're on all the doors except the driver's door.)

Any help? Anyone...anyone?