I have never had one not work. Sometimes after changing the battery, the have to be paired to the main panel. I don't have access to my rig right now, but I believe it is through the settings menu. If no luck, you can order one by calling Firefly. 574-825-4600 They have been quite helpful when I had a question.
Vicki and Mike, Aria 3901- The Wined Up Bus, towing 16 Jeep JKUR.