I have to install an automatic trunk opener for Model 3. Tesla will not install aftermarket parts and none of the authorized repair shops (here in Dubai) want to do it. Before I install this, I want to power shutdown to make sure none of the systems are damaged as the wiring is installed/connected. What is the best way to do this? The Power Off button on the display scares me since the car turns back on if you do anything. I heard about a "Service Mode". Does that have a proper power shutdown option? If yes, how to I enable it?