Key not working

[abh29]

Back Again,

My normal key not opening door on remote , open with key and alarm going off.
Spare key ,bought new from dealer last year, works perfect.
Hoping original key just requires a new battery, we have never changed it in 5 years.
Any ideas , and if so how do I change the battery.

 

[Grumps]

There is a small Phillips screw head on the back of the remote. Undo and the back lifts off. Change battery within 12 seconds or you may have to re-program the fob. Changed mine and it was fine.

 

[abh29]

Thanks for that ,as I only have 12 seconds I will need to get a battery before I start , any ideas as to the type of battery. I can not find it in handbook
Thanks

 

[Low Rider]

Take the back off without removing the battery and make a note of the number

 

[abh29]

Sorry ,misunderstood to read it as from removing back to replacing back.