I have a Blinder M-20 system installed from http://www.blinder.dk/. The system is about 2 years old and has been installed/uninstalled twice. The unit still seems to work but after turning it on (i.e. Ignition turned) it sends out an audible tone for about two seconds (normal) but then after about a minute (or more) the buzzer sounds again for about one second. The buzzer can also randomly sound during a journey. I've checked for loose power connections and connetions to the junction box. Its this normal or what is the fault?
PS: Is there anything to test the Blinders other than the Tester sold by www.radarbusters.com ?