1999 Mercury Mountaineer Door Latch/Lock Malfunctioning

[swasheck]

I have an odd issue with the driver side door of a '99 Mercury Mountaineer. This was a kid's car so it's been through some things like door slams and aggressive handle use, but here are the symptoms:
1. Driver side control will lock but will not unlock the doors. It simply does not engage when unlock is pressed
2. Passenger side control works as expected, locks and unlocks all doors.
3. Key will unlock passenger side door, but will only partially lift the lock when unlocking driver side (once or twice I've gotten it to fully lift with a jiggle). Usually the driver side will not even turn in the lock, though.
4. Need to replace external handle because it seems that the springs have been ruined (likely due to frustration)
5. There is a gap between the mechanism from the external handle and the rod inside the door that opens the latch. Interior handle works as expected.

Also - the remote lock/unlock has long since been lost so I've not been able to test that.

My sense is that replacing the exterior handle to open the door will solve some problems, but I'm not sure about the lock. Does this sound correct?

 

[EB4X]

1. Maybe the "unlock" lead/wire got damaged in wire harness/boot in your door jamb...sometimes a wire will get damaged there, somewhat rare but does happen, of course could be switch bad / or contact grimy, might want to take out and spray with electronics cleaner.
3. I'd spray some lubricant inside key hole for starters, and if your taking panel off for #1 saturate entire rod assembly inside with lubricant.
Here's vid on tips to remove panel....take note at 3:30 mark for removing switch panel:

 

[Explo5ohh]

I had a similar issue with my 99 Explorer. Key wouldn't turn the lock and the key fob wouldn't move it either. I replaced the door lock actuator, thinking that was the problem, and maybe it partly was, but I ended up using a spring to pull up on the lock rod that comes up through the door panel. I found this video on YouTube when I was working on mine. He went to the junkyard to find a spring, but I just used one that I had on a old small engine carburetor that was laying around. Just look and see how long of one you may need and go to a hardware store and grab a couple. It doesn't need to be a really strong spring, just something to hold a little upwards tension on the rod.

 

[Pete Deering]

Nice video, you can look at the passenger side door lock too see, what the spring looks like and attached too.

 

[swasheck]

Thank you all so much. I also have a VW Beetle project I'm working on, but will try this tomorrow. Thanks again.

 

[swasheck]

this worked. thank you!!

 

[EB4X]

this worked. thank you!!

Which part (s) / procedures worked? ....

 

[swasheck]

Which part (s) / procedures worked? ....

the spring creating tension worked for unlocking the door with the keys. other problems remain