On a recent trip with our 2018 Forest River Sunseeker 3270 Class C motorhome, we fell victim to the dreaded TriMark door lock failure. We were camped out at a race track for a long weekend when we discovered that we could no longer open the side door of the motorhome from either the inside or outside. Fortunately, since we have a Class C, we were able to get in and out of the rig using the cab doors. For this reason, I did not attempt a repair while at the track because I didnít want to take the chance of opening a can of worms and have a door that would not stay closed on the trip home.
Once we got home, I removed the inner part of the door lock and was able to extract the broken latch pieces from the mechanism. At this point, the side door could be opened, making it much easier to unload everything from the long weekend trip. Also, the door could be secured with the deadbolt, which was still operable, making it safe to drive or park the rig overnight.
I did some internet research and came to find out that we were not the first to experience failure of the die cast zinc (pot metal) latch which, in my opinion as a former mechanical engineer and guy who has repaired his own vehicles for the past 50+ years, is an unsuitable material for this application. However, it probably saved the manufacturer about fifty cents, so it was obviously justified.
Once I realized that a new door lock assembly would be required, I started a web search to find one. I determined that the part was a TriMark 601650 Door Handle (Black). The best price I could find was from Amazon at $93.37 with free Prime shipping. Here is the link: https://www.amazon.com/dp/B00HE7SLF8..._F9axFb6X6QHR3
. The price has gone up to $101.45 at this time, but is probably still a good deal.
When I received the new lock, I first checked the latch with my magnet and fortunately it is made of steel, much stronger that the old part. The installation was straightforward, except for two small tabs on the deadbolt mechanism that had to be removed. I used a cutoff wheel in a Dremel tool for this; I had to go slow because these tabs were also made from a non-ferrous material. After cutting the tabs, I used a cylindrical stone in the Dremel to smooth and round over the edges.
After that, the new lock went in easily and worked much more smoothly than the old one. I also expect it to last much longer. The new lock came with a replacement striker plate, but I did not use it because the old one was fine.
I am including some pictures to help anyone else who has this problem.