I am suspicious that my BLINDER M-20 does not actually work. When I turn the jammer on I hear a very faint and quick "brap" and the light is green the entire time. Is this normal? Is there any common installation errors that may account for something like this? I am trying to avoid spending another $30 some odd dollars to buy a specific tester so if you have any other options i'd love to know. I've read on here that it's supposed to make a somewhat loud tone, go quiet and then 15-30 seconds later have another tone (indicating "test" mode is over) is this true? Please, I would appreciate any information you may have on the subject as I do not want to pay $350 for something that doesn't work.