Rear Hatch Actuator

The rear hatch actuator on my Hyundai Tuscani does not function properly. I've replaced it with a new part with the same result. So then I testing the electrical wiring to the actuator to find 12V DC and .5A flowing to the device. I don't know much about cars but .5 amps in the electrical world doesn't seem like it's enough. Not to mention that when I engage the actuator it actually moves but seems not to be strong enough to unlock the hatch. I tested the power again with one lead grounded to the chassis instead of the ground wire in the harness with the same result.

My first question is does anyone know what an appropriate amperage for this device. My second would be does anyone have any suggestions other than a rewire as to what could be the problem and how I would go about fixing it?

Thanks in advance,
- Jason