I have a 2003 G35 Coupe and my door lock from the outside is hit or miss. For starters, my passenger door doesnt respond to either a key fob, the outside manual lock or inside buttons. To lock it i gotta manually flick the switch. I bought that car knowing that problem. Now, my outside manual lock is 50/50. Sometimes when i go to unlock it (i dont have a fob cuz they only last a week for some reason then the battery keeps dying) the door will unlock but the car alarm will go off. Ive realized that i have to hold it until the windows go down to make sure its actually unlocked. Does anyone know what could be causing this? A fuse? A short? Messed up connections? Thats a few ideas ive had but dont know where to start looking.

 

There are threads about this if you search. One of the linkages in there gets rusty and stops moving reliably. You should deal with it now before it gets worse and you can't get it to unlock.