My 07 Fusion has been having problems with locking. Mainly due to the fact that it thinks the doors are sometimes open when they're not, however my other problem is that most of the time when it does decide it will lock, the 'double lock' function will not work. So I'll lock it however if I press the lock button a second time it won't do anything whereas it should double lock so the handles cant be used from the inside. Any advice on what that could be, as I'm not 100% sure if it'd be completely related to the door sensors not knowing whether the doors are open or not. 

any help would be appreciated, thanks

Hi Josh, I have just purchased a 2007 Fusion. It had the same “door open” issue you have. I purchased a large can of electrical contact cleaner and a can of dry lubricant. If you start with the door that is causing the problem the most. Open the door and using a screw driver lock the catch in all the way by pushing it towards the outside of the door. Then spray lots of contact cleaner up into the gap above the latch and into the latch mechanism below. Then use the door handle to release the latch and push it all the way back to the lock position again. Do this lots of times, occasionally wiping the excess fluid. Shut the door and see if the dash has cleared the fault. If not then just repeat. Repeat for all the door latches. Also change the battery in the key, my one was running flat so wouldn’t lock the car properly. Hope this helps! 🙂