I'm trying to install power locks in my manual car. I have the wire harness installed and powered, the switches and actuators tested good. But when I try to test the whole system none of the actuators work? I tested the circuit everywhere and everywhere I checked it had 12v. I tested the connectors on the actuators and they get both get 12v when the switch is depressed. What is wrong, I never hooked up a ground but my friend says the body of the actuator acts as a ground. Any suggestions?

 

Make sure the body of the actuator is grounded to the car...anything metal...clean it up nice and ground it out