Central locking tailgate 306 Break, Bj 99

Hello people, from today to tomorrow the central locking on the tailgate did not go at my Peugeot 306 Break, Bj99. The 4 doors go perfectly. I removed the actuator from the tailgate and on the desk it goes perfectly with 12 V. It drives in and out with poles at 12 V. On the plug to the actuator on the tailgate there is no tension when I measure with the digital multimeter. When I operate the central locking the multimeter coughs at best Unfortunately I didn’t get any further? Does anyone have a hint? Where is the controller for the ZV during the break? I found nothing under the back seat or backrest as written here in the forum. Under the back bench there are only two covers in the carpet, where I guess the fuel pump or filter now. I am grateful for hints! Greetings