This was done on 2002 megane.
Renault megane back door wont lock.
I put together a how to guide to.
When you lock the car which you can do with the buttons on the keycard the buttons on the handles if they still work they were a bit intermittent on my 2003 mégane or the black button in the centre of the renault diamond on the boot lid you have about 3 seconds to check that the doors are locked by pulling on the handles.
As you changed the lock yourself you will know how to access the lock by lifting the fabric.
Replacing the door lock actuator on the passenger side of a renault megane from 1999.
Door lock unlock problem post by chrism mon may 18 2009 2 23 pm my card is on its way back from gary at www keyrepair co uk i also had to use my spare seems my card stopped sending a signal to the vehicle however for a 27 charge gary has sorted it out for me card should be with me by tuesday.
This process will work with any kind of megane from around the same time.
This video just shows a quick way to open a megane rear door if the child locks are on and the door handle breaks a common fault.