Need perhaps a few ideas or some advice on this .....

start up the car no problem:

1st thing that happens is after 30-40 sec of driving , central locking keeps locking then unlocking non stop for about 10secs

2nd after about say 5 mins of driving then car , lights start dimming in dashboard and headlights slighty



the car has just been fitted with new alternator and battery, so any help on this would be great as now a little confused