So, how old is the trailer? Yes they need replacing but I have one in my 2006 trailer that is still working.
Here are a couple of things to check. If the battery in the trailer gets low you would usually hear a chirping sound. This usually happens in the dead of night by the way. I remember during once such night the light was yellow.
My batteries were fine so I went online to a forum like this one and was told that sometimes these things accumulate dirt and dust and that can cause a problem. Mine had a "reset" or "check" button, or was it a "test" button? I pressed that and everything went back to normal. I was going to try to simply blow it out with compressed air if that didn't work. Since yours isn't making the chirping sound my guess is that you probably need a new one.
Good luck. Come back and share your solution here.
2017 Toyota Tundra, Double Cab, 5.7L V8
2006 Airstream 25 FB SE
Equalizer Hitch