Hello again. Just a couple of clarifications:

1. Rfoster, as I mentioned in my original post, I had the keys in my hand. And I also have a spare hidden away for outside access.

2. GaryDe and Rfoster, the Marathon system does not use a key to unlock the door if locked with the fob. other converters may well be different. My point in posting this is that everyone should be aware how their individual coach is set up.

3. Ray Davis, you are right, and Marathon and Prevost both suggested that method of removing electrical power, which I tried, it did not work. Sorry I forgot to mention that because that is another reason this problem can be such a pain.

4. Jon, your Liberty is different, note below. And your other points are on the money. We try to prepare for eventualities, but can not possibly cover them all. I posted this problem mostly because there are many Marathon conversions and owners should be aware of this particular glitch.


My Marathon entry door has 3 "locks".

One has no key and is the latching mechanism operated by the handles on the inside and outside of the door. It grabs the pin sticking out into the doorway on the left side as you enter and clicks the door closed when you slam it. (Once upon a time this mechanism broke inside the door and we were trapped inside, since all my tools were in the bay. I now carry a phillips screwdriver and 2 allen wrenches inside the coach to remove the inside door skin to access the mechanism.)

The second lock is a deadbolt in the door, operated by a key on the outside and a finger latch on the inside.

The third lock is an electrically controlled but air operated latch mounted on the coach body door jamb. This is controlled by the switche next to the door, switch on the dash by the driver, and in our case, by the key fob from the alarm system. We always latch the door when driving with this lock, and have always until now used it when we leave the coach. This is the lock that would not open. Removing air and/or electricity had no affect on the lock, except when we turned off all the electricity the alarm siren began to sound. it is apparently wired directly to the batteries and may explain a very small current drain even if the batteries are disconnected ( 35 milliamps according to the alarm manual).

So to sum up, I plan to install another switch, accessible from the outside, to unlock this third lock in case of fob failure in the future. (I was able to reprogram my fob, and the alarm and fob work correctly again.)

I sincerely hope this thread helps at least one reader avoid this problem in the future.