Mine has been on the fritz lately too, when there's a lot of other radios being operated nearby. The light on the back of the module won't light, it simply won't find a signal. I think that light signifies that the module has locked onto a channel and that's what it connects to the receiver with. If the light doesn't come on, the module isn't finding a channel and isn't locking to one.

From the sound of it, the module may just be bad.