Liftmaster transmitters not working
I have an older model Liftmaster. All of a sudden, the transmitters will not operate the door. The unit works fine when using the wall switch, but of course it is hard wired to the unit. I have checked the batteries on the transmitters and they seem to be working fine (at least the LED lights up when button is depressed). Is this a receiver issue? If so, what does the receiver do, and how do I replace it?