Has anyone had experience with a Mondeo central locking system with a mind of it's own?

My Y reg 2000 ghia will occasionally unlock itself again whilst driving along and even on occasion lock all doors as well. Has been known to do this whilst stationary too.

It also occasionally loses the timer on the internal light after you get in. You know the one that supposed to stay on for x seconds or until the ignition is turned on.

I changed the key fob battery but am baffled.

Where is the control box?
Any other people experienced this?
Any clues?

Cheers

Tels