My rear driver's side door won't lock on my 2010 F-150 Lariat crewcab. I purchased a new lock Actuator/door Latch & installed it. But still the door doesn't lock. Could it be a fuse? Or am I missing something altogether that is really simply? Or is it something that might be a little more? I am a disabled veteran & trying to reach to manual lock & unlock the door is very difficult for me. Please, any advice, suggestions & or help would be greatly appreciated. Thank you in advance for any & all suggestions.