No heat on drivers side

There are two different actuators, one is the drivers side the other the passenger side. If the one you replaced was on the lower drivers side then it should be the correct one. However, it is possible that it is not the actuator that is bad, there are doors inside the case that can break or it may be that the actuator wiring is faulty or the control head itself. The common failure is the actuator but the other fail as well.
It is possible to test the actuator from the wiring to the control head but it is not a DIY thing unless you have the proper scan tool to send the control signals and monitor what the controls see from the actuator because it uses a 0 - 2.5 - 5 volt signal pattern to move the actuator.

Could very well be, as I said actuators are the common failure item but since you need to pull everything apart to even test them it is usually faster to just replace them. But I also test them because it could be the wiring or the control head itself and you already have the dash out by then.