Open the Hörmann hand transmitter housing and change the battery
Youtube video instructions Hörmann radio remote control battery change. I will show you how you can replace the batteries in the HSE2 HSE 2 hand-held transmitter and how you can open and close the hand-held transmitter or open the housing. If the battery in the hand transmitter of the Hörmann garage door is empty, the batteries must be replaced.
Buy cheap CR2032 battery for hand transmitter: https://amzn.to/3CNL3Ls