Key unlocking door has nothing to do with the battery. Fob unlocking the door does have something to do with the battery.

Did the key ever unlock the door? I am guessing that someone replaced the ignition cylinder or the door cylinder without changing the other.

Your solution is get a locksmith.

 

The key lock is mechanical. Doesn't need battery power. Sounds like your key/lock/mechanism is just stuck. Most people don't ever use them since these cars have remote entry key fobs, thus the key cylinder gets clogged with road dirt and dust and won't turn.

Really ? You don't know what year your car is ?

 

the Key used to unlock it just fine.

i inherited the car 6 years ago so I don’t know what year it is because there was never a need to know until now.

i will try to find a lock smith

 

Never looked at the registration? Or got insurance?

The 10th digit of the VIN is the year, if all else fails (A for 10, 9 for 2009. B for 2011, etc) That's the plate on the dashboard that you can see from outside on the driver side.

But, the key locking/unlocking the door has nothing to do with the battery on any year.

 

 

Once they figure out how to open the rear hatch to get at it....

 

 

You could look in your Owner Manual for instruction on how to open the hatch and how to hook jumper cables up under the hood.. Owner Manual available for free via the link in my sig.