Hi my Central locking will lock the car but wont unlock it. (I have to use key to open it) the boot opens with fob also car alarm is fine. so the fob works and that. its just the unlock that wont work i can use the key so i can get in but I would still like it to work again. thanks for your help
We need more information here. Does this happen both with the fob and with the lock switch inside the car? Do you hear any noise at all when you try the lock switch inside the car?
I used to have the very same problem on my Nissan Pathfinder and on old Nissan Sentra remotes and what did not work was a button on remote itself, so it’s not that uncommon. Probably this button gets used more, so it wears out first.
Auto parts stores usually have a stand with replacement batteries where you can point with your remote to test “battery strength”, where it tests for how strong RF signal your remote emits. You can try there if your “unlock” button results in any RF coming out.
Do you have a second fob? what happens with that?
the inside lock/unlock button is the same as the key fob (it locked the car but did would not unlock it). on the key fob boot button will open boot, lock car button will lock car and the alarm activated, unlock button will deactivated alarm but wont unlock the door also makes no noise. the key works in the door and the up/down lever on each door (dont know the name of it) will work from the inside lock and unlock each door.
also other fob is same
Well, y’know, I think Nash Metropolitans were designed this way… 
C’mon, man, give us something to work with here. Year, make, model, options package, mileage.
Also, has your battery gone dead or been changed lately? Any repairs or maintenance been done recently?
05 plate, rover 25, battery works fine central locking is screwed up, what do you need to know?
Well that’s more than I want to know…
The first issue would be the fob itself, otherwise its to the dealer. I just replaced my two fobs. The one would only operate the trunk and the other would only lock the car when the fob was warm. Everything works fine now. They do wear out.
The door lock mechanism is inside the door (duh!) and NEVER gets lubricated. Water can get in there, dust certainly, and after 10 years you can be pretty certain that any grease that was in there has slid down away from the surfaces it lubricated. If you have tools and some skill, take off the inside door cover and lube those latches and the operating mechanism, and while you are doing that, lube the window tracks as well.
Who knows, it might work.