Awhile back I brought up a topic where my PTL entry door started to lock itself. At first I thought perhaps the electric lock/alarm remote was the culprit but quickly ruled that out as the bay doors did not lock...only the entry door. This problem continued to get worse until it could be replicated quite easily. About once in three time the door was closed you could hear it lock.
Last week I dug into the problem and pulled off the door hardware and carpet. Once it was off you can easily see the mechanism but figuring out how it works takes a bit of noodling. If you look at the first picture you will see:
A) The electric actuator. Turquoise cylinder in the lower left extends when locking and causes the door handles to be disengaged from the latch.
B) Near the top is the inside door handle connected to the cam mechanism by what looks like a turnbuckle but isn't.
C) Right under the inside handle is the inside door lock also connection to the cam mechanism.
D) On the lower right is another turnbuckle. This is the arm for the outside door handle.
E) Last but not least. On the right side is a brass colored arm with a little lever under it. This is the arm for the door latch thing that latches the door closed. The little lever under it lifts the arm to release the latch and seems to be the cause of all the mischief.
In the second pic you can see the relation ship between the lever and latch arm. What happens is that when the door is commanded to lock either manually or electrically this lever rotates inward and disengages from the arm. This effectively disengages both door handles and the door will not unlatch. Notice that there is minimal engagement with arm. Due to age the lever is fairly loose on its pivot and you can move it back so it almost disengages completely. (Note: the lever was actually a bit further to the left than is shown in the picture when I started) I think what happened is that when the door was forcefully closed the lever jumped left and up disengaged the door handles.
I believe the root cause was wear over time on the latch pivot and the plastic eye located on the electric plunger where the locking arm attaches.
The solution was to move the connector for the solenoid shaft and locking rod to allow more engagement of the suspect lever. I loosened the set screw on the solenoid shaft in slide it back about 1/4". This immediately increased the lever/arm engagement by about the same amount.
Once this was done it also required adjusting both door handles as the release point was significantly changed. You can see the slop where the rod engages the cam mechanism. To do this you need to loosen the nut on the cam side, pop the little clip loose from the rod, pull the rod out and tighten it one full turn or so until all the slack is removed.
If you look at the third pic you can see how much more engagement the lever has with the release arm.
It appears that this fix worked and my door no longer self locks. Only time will tell for sure and in the meantime I will keep a door key in a convenient outside location.
