Red Key Fob Not Working

I know, I know, the subject of key fobs is many and long. I have a problem with my Red Fob, and the Black Fob is working. When the Red Fobs button is pressed the indicator led on the Fob is very dim and flickers. The Black Fob works great, no issues.

After searching this website and a few other places and I have not come up with anything useful. I checked the battery voltage on the existing battery and it was 12.07 vdc. The indicator led on the Fob is very dim and flickers. I've cleaned the battery contacts with a pencil eraser and then methyl alcohol and used a new battery with the same results

Anyone have a hunch on what it is?

Waiting on the edge of my seat.

 

Well, after preforming a suggested post, changing battery from know good one, and see if it works. I had the A23 double pack in my battery drawer purchased these 1-1/2 years ago. I assumed they were good being they are in the original bubble pack card and the batteries measured 12.07 vdc. I bought these two years ago. I've had Duracell and Energizer batteries that said they were good until 2025.

I guess I should load test these batteries before I store them...

Total success, The swapped battery worked in the RedFob. I was thinking I would need to go the high cost road of serval thousand dollars and replace the entire system.