One thing you can do is check to see if you have 12 volts going to the lock mechanism.
There are two tabs on the door jamb. Use your meter to see if there is 12+ volts there.
You might also try to reprogram the keypad to the receiver.
Instructions can be found
HERE. (In the Heartland Owners Manuals) found in Tools at the top of the page.
I had the Southco Keyless Entry that worked great for 2 years in our BH.
Then when it quit I just bought the
RVLock and now enjoy a remote keyfob.
Yeah, I hate research projects as well, but sometimes it's what we gotta do.
Oh, I created a new thread for your post.
Peace
Dave