I have been dealing with this for two years now.
My first tri mark lock broke twice after a year ..Thor sent me a new one and that just broke for the second time. they break at two spots the little plastic piece and the plunger ...have had both locks break both so all total I have bean locked out 4 times.
Trimark sells a steel plunger (upgraded version ) but you have to call them and request it at $200 .( wife talked to them week and half ago).
so I bought the rv lock for my ace ...
https://www.rvlock.com/collections/f...oducts/class-c
Installed it and didn't work...
The screen door would have to be modified to make the lock work...
The lock handle hits by about a 1/4".
I just sent it back and bought the bauer lock..
https://www.rvupgradestore.com/Bauer...0342491BB56019
The bauer lock fit but the door is difficult to close unless you use the handle and retract the plunger...
I am hoping I can do some more adjustment and fix it.
by the way see this thread too
http://www.thorforums.com/forums/f4/...ocks-8142.html
Hope this helps