How do I replace the battery in the key

I replaced one in my first key but it does not work is there a sequence to follow

Ian

No sequence, the remote should work if the battery is good.

Check the microswitch as this is a known weak point (usually becomes unsoldered and can be repaired at a good electronic shop).
Multimeter would be good to check voltage on fob.

Thanks will try that tomorrow

Ian

Checked the battery this morning plenty power so decide to open the first key and study it only to I had fitted the battery the wrong way round

Light does not work if battery if fitted incorrectly

Both now working

Thanks for your reply

Ian