Since the keyless entry system stopped working last year, I've had to use t
he old-fashioned keyed locks, and number pad, to access my 1998 Mercury Gra
Driver door and trunk locks work flawlessly, but the passenger door lock is
uncooperative. It seems as if it only works when the temperature is somew
hat warm - let's say, above 50°F. Which it is here only sometimes in the
afternoon, this being winter in my area.
It goes like this: I'll insert the key, attempt to turn it...but, it doesn'
t. Maybe wiggles a little. That's it. I'm not going to force it, since I
don't want to break the key off in the lock, and it probably still wouldn'
At least part of the locking mechanism does function. I can unlock and loc
k the passenger door from either the driver's side number pad, or door-moun
ted lock/unlock switches (both driver and passenger side). It's only direc
tly turning the lock with the key which doesn't work.
I've tried rattling the key in the lock. No good.
I've tried my extra key. No difference.
I've squirted some graphite lube in the keyhole. That helped when the lock
stopped wanting to turn a couple of years ago. This time, it didn't help.
I'm reluctant to put anything else in the keyhole. Someone suggested WD-40
, but that seems like a terrible idea, since it's not actually a lubricant.
3-in-1 or other oil could gunk up something sensitive.
Ours is a very dry climate, so I doubt anything is binding up due to rust a
Short of taking this to a mechanic, any ideas?
How much of a project would it be to swap out the lock myself? Am I going
to run into headaches due to the vehicle's notorious first-generation PATS?
It's weird that the *passenger*
door lock has seemingly worn out, since it'
s the driver side lock that gets used most often.