furnace help

[geezerbob]

Our son is out with our camper and has a question. He is running the furnace and the furnace fan comes on like it should but the overheard fan on the ac comes on also. He is running off a generator which shouldn't make any difference. On our 2016 23 rls the heat only blows out of the furnace and the ac air comes out of the over head ducts. I'm not near them now but isn't there a function on the thermostat to shut off that ac over head fan. Or am I missing something here.
Bob

[anav8or]

Are you certain your ac unit isn't also a heat pump?

[geezerbob]

Not on anything that I have read and I have the manual for that unit.
a 13.5 k
Bob

[wiscampsin]

Have him try setting the fan setting on the T-stat to 'AUTO".