I had exactly the same symptoms as the
OP...so was sure this re-programming the remote would solve my problem...but it didn't.
So I took the opportunity to go through the bag of spare remote keypads/keyfobs I have collected over the years, tested all of them and these are the problems I found, after opening them up;
- the battery cradle had broken away from the printed circuit board...the gradualness of this process must have been why mine did work some of the time...until it stopped altogether
- on the other side of the printed circuit board, one of the button contacts had broken off one remote
- sometimes I found that a button when pressed through the rubber would not work and also the red led did not come on. However when opened up, I could press the contact on the printed circuit board directly and the red led would light up. In all cases after a thorough spray and clean with alcohol, I was able to make the buttons work when re-assembled. From the colour that came off and sometimes the stickiness, I presume this problem is caused by spillage.
Note - even when fully cleaned, some remotes just press and respond better than others.