How to change batteries of the remote control of the central door mechanism

what does the manual say?

(T1215)to open and close the doors and to activate the alarm. Because the handheld is not working anymore I´ve changed the 4 battery´s (GP 391), but it´s still not working.My dealer told me I´ve destroid the handheld by placing the battery´s the wrong way.

be where ?

The two batteries at one end have the positive connection uppermost when putting them into the remote control. The other two have their negative poles uppermost. Thoroughly clean the batteries contact areas and the spring contacts in the screw on lid and case then replace the batteries observing the correct p[polarities. The positive poles are the case and are marked "+", whereas the negative poles are unmarked and have a ring insulator around them. When your remote control seems to be getting weak carry out the steps above and you will regain the use of your remote. You should regain use of the control just by carrying out the above steps.

Cheers, Peter.

The solution of peter has solved the problem, thanks