The units should connect automatically when there are full batteries in both. Switch on the tractor first and then the transmitter. If the transmitter flashes, the connection has been established. If the transmitter does not flash, they are not connected. Depending on the age and serial number 1 or 2, which can be found on the underside of the vehicle, the products are not compatible. If this is the case, please contact customer service! https://helpcenter.galaxus.ch/hc...