low pressure air alarm not working properly, ADVICE APPRECIATED

Since i bought the truck several months ago the low air pressure alarm has not worked properly. (I never drove the truck commercially yet). The dash low air pressure symbol alarm goes off correctly with a barely audible alarm from the dash (NOT THE BUZZER). When pressure builds past the the low pressure cut off point the dash onl alarm symbol goes off and the dim chine. I at first thought maybe the buzzer itself was bad. But then i finally learned how this oddly built rear air bags DUMP VALVE works and unarmed/flipped the switch and as rear air bags dumped pressure, amazing the low air pressure BUZZER screamed alive, it was only until i turned the dump valve back off, the buzzer stopped. The buzzer will ONLY work if the dump valve is activated.

To date i have changed out all of the air pressure switches in the dash and even swapped around the connectors. I am somewhat at a loss what to do next... wonder if there is a way to splice into the switch that alerts the dash alarm to go off, and tie that into the buzzer somehow... Oh i own a FL112 2002 freightliner.

 

any advice? again the buzzer goes off when the dump switch is activated but nothing when the toggle switch is off the air pressure falls

 

are there more air switches other than the large group behind the dash? I'm confused now. As stated above I replaced all the air switches behind the dash. (about 4 or 5 of them)

 

i never said air is falling... air is holding just fine. THE BUZZER IS NOT GOING OFF. thats the irritating frustrating problem i am having. I can only get the low air alarm/buzzer to go off when i hit the dump valve. The dash low air alarm goes off correctly however.