Kind of an odd situation... hopefully someone can figure out what the heck is going on?

1. I have 2 sets of key fobs... both are OEM with remote start. I've used one set for life of vehicle... the 2nd set is back up... hardly used.
2. On the original set I've used for life... I've noticed the remote start wasn't working. Seemingly harder to push down the lock button. No big deal... changed the battery lock, unlock, and remote power lift gate all worked better. But, I still couldn't use my remote start on Key Fob (original). The 2nd set all functions work properly including remote start.
3. Haven't driven my vehicle in a long time mysteriously both key fobs are not responding. I noticed this when trying to reset tire pressure sensors on all 4 tires after a tire rotation.
4. I tried to reprogram the key fob using "Remote Key Learning" on dash and it won't respond at all. No beeps.. no horn... no chirping... nothing.

So everything is at a stand still at the moment. I'm sort of stuck. I don't know what I should do next or what to check for? Anyone have any ideas?

 

Check batteries?