OK, spray a LIBERAL AMOUNT OF WD40 into the door latch on the body
frame ;-)

I have to do this with white lithium grease ALL THE TIME on my door
hinges, and such, just to keep them lubed properly, because the lube
dries out !  The White Grease dries out and becomes, just useless.

So SPRAY GENEROUSLY, AND SPRAY OFTEN ;)

Also, while you're at it, check your wheel lug nuts for correct
torque.  Just yesterday I discovered my RF wheel lugs coming loose (
no lube on them thanks anyhow ).  Had I not done this undocumented
"check" the wheel was on its' way to coming off the hub.  

You might not have to check if you have steel wheels; mine are
aluminum alloy, so need to be checked every now and then.

BTW, I go through so much WD40 around here, I'm seriously thinking
about buying it by the gallon.  I use it to lube the augers and chutes
on my snow machinery so the snow doesn't clog up the works.  And I use
it all over my car.  For me, it works as advertised.
YMMV

Lg