I had a bit of a fight to program our lock on a Seneca 37HJ as there was no manual, and the instructions on the back of the battery compartment did not work. A bit of sleuthing pointed me in the right direction, and I found that if I removed the batteries for 10 seconds or so and re-inserted them, the instructions on the back of the unit worked fine.
Background: The instructions on the back made no sense to me since they did not require I enter the current code in any way, but when I saw someone talk about resetting to default (which was a different code than what my unit had), I put 2+2 together, and got it working. Basically the reset only works if you are currently running the default code, which the reset ensures.
Word to the wise, if you have your door unlocked, and see a friend who likes practical jokes lurking near your door with a philips head screwdriver, keep an eye on them