I have a 2000 v6 mustang and my door locks don't work like they should. Went I use my keypad it will unlock my driver door 20% of the time but never my passenger side. Most of the time I need to use the key in the door to unlock it and reach over and pull the handle to unlock the passenger side door. How do I fix this so when I hit lock or unlock on the door or keypad, my doors lock and unlock? I'm guessing I will need to take off the door panels but after that I'm lost. What needs to be fixed or adjusted to fix this. Also, my passenger side door has never worked, I've always had to lock it manually and unlock it buy opening the handel.