its cold as &$%# snow blizzard and you aint got (yeah- aint got) no air pressure over 40 lbs, buzzer winding, heat quit, engine shutdown, freezing....

cut engine off.
wait 5 minutes for ECM (brain) to reset.
turn key to on position.
push in both brake valves and pump brakes to '0' air pressure.
turn key off.
wait 5 more minutes.
crank engine.
pressure should build to 100 pounds or so.

if this does not fix- the air compressor governor is shot.
small part around $30 located on the same piece (driver side engine) with fuel pump- but get road call shop to replace it- trust me

if this was usefull drop a quick post of thanks