OK, all the trailers I have owned have had dual door locks.  My current 177SE uses the same key for both (and I think this has been the case in my past trailers).  I know one lock operates a dead bolt (which can unlock from the inside) and one lock latches the handle.  

My question is why do we need both?  Wouldn't just a dead bolt lock be enough?
Bob Merriman
2017 Retro 177SE 
2015 Ford F150 2.7L Ecoboost
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It is my understanding that the deadbolt locks are different on all trailers (to a point) and the other lock is mastered to dealer keys. So, in theory if you take your trailer to the dealer for service and lock the deadbolt lock the dealer can't open it.
That's how they explained it to me, as they checked to make sure I didn't lock it! Hope that makes sense.
2015 177 SE
1990 Chevy Suburban 5.7L
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Yep. Roccosamore is right. The deadbolt can only be opened with your exact key cut. There's a master key which will open the latch lock.

Make sure you have your key number recorded somewhere.
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Ralph L Staub
That is my understanding as well.
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Lisa Foster Moss
We made some extra copies and tried them out just to make sure they worked. They did.
Fun Fact: If you accidentally lock yourself out of the bathroom, (stupid story), the same key will open it up. 
Don & Lisa Moss
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So on my last RV I found that all had the same keys! Your keys would open anyone elses and vice versa. I then purchased from Amazon an RVLock v3 Keyless handle with wireless keypad and removte Fob and solved the issue. RVLock V3 Keyless Handle w/ Wireless Keypad & Remote Fob: Automotive
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