Originally Posted by jim heffel
The Safari Trek engine is a 8.1 L gasoline w/electronic fuel injection, 496 cu in, 340 hp and it does have air horns
In that case I believe you are correct that what you hear running is most likely the 12V air compressor for the air horn air supply.
When the key is 1st turned on it should pump up to a preset pressure and shut off...(mine runs for a few minutes whenever the key is first turned on after the coach sits overnight or longer, or if I use the air horns).
Check the air pump, the air lines and the air tank for leaks.