Hi just wondering if some can advise,

Rencently my remote central locking stopped working on my 2004 Voyager 2.4 SE. I have checked the battery which seems ok, the remotes seem completly dead, however it is working perfectly normal manually from the internal door switches and continues to auto lock when driving off. I have notice the little light on the dash by the speedometer has stopped flashing, any advise would be very much appriciated as dont wish to be ripped off by expensive dealers.