The standard 3 button fob has seen better days so I bought a replacement with the intention of swapping the key blade and circuit board over from the original, along with a new battery. As I was only supplied with the one fob when I bought the car, I’m worried that if the board is without power, then it will loose its connection to the car and I don’t have the ‘secondary’ key to perform a re-sync procedure. Is there a time window where the battery can be replaced in the fob without it losing its stored frequencies/settings? Also, my fob is the version with a metal pin securing the two halves of the case together, unlike my partners VW of the same age who’s fob comes apart by prising it open with a flat blade screwdriver, does this have any bearing on the affects of removing the battery?
