VEHICLE WAS PARKED WITH PARKING BRAKE ON IN MY DRIVEWAY FOR 3 DAYS . PARKING BRAKES FAILED AN THE MOTORHOME ROLLED OFF MY DRIVEWAY AND INTO THE YARD HITTING ONE OF MY OTHER VEHICLES. AFTER CONTACTING NEWMAR AND FREIGHTLINER I WAS INFORMED THAT A PRESSURE SWITCH HAD FAILED AND CAUSED THE BRAKES TO RELEASE. WHAT IF THIS HAD HAPPENED AT A GAS STATION WITH MY FAMILY IN IT. THE LIGHTS IN THE DASHBOARD INDICATE THE PARKING BRAKES ARE INGUAGED BUT THERE ARE NO BRAKES. THE PART FREIGHTLINER SAID FAILED IS 06-32698-000 SWITCH-PRESSURE