Centralized closure kia sportage 2000 td

Hello,
I have a Kia Sportage 2000 TD 83 hp of the year 2000.
The problem is of central locking, say that it has no remote control therefore closes and opens with the key.
To close there is no problem, you give the key and close perfectly the four doors all the times you give it, the problem comes for the opening, every 100 times opens the four doors (very few), of course that the driver's door always.
Giving this type of failure, what can it be?
Any of you have happened to you?
Is it a relay or switchboard problem?
Well I don't spread anymore and I hope I explained.
Thanks
greetings